April 25th, 2013 
CryptoBadger In this fifth and final installment of our litecoin mining rig guide, I’ll answer some common questions about building your own rig, profit expectations, and mining in general. If you’ve read the rest of the guide and still have some lingering questions, you might find the answers you’re looking for here.
Hit the “read more” button for the FAQ!
Build a Litecoin Mining Rig, part 5: Mining FAQ
General Questions
- So how much money can I expect to make from mining, exactly?
- Why not just buy litecoins (or bitcoins) directly, and then sell them later at a profit?
- How noisy/hot are these rigs?
- How do I convince my significant other that building a rig is a good idea?
Technical Questions
- How do I turn my computer on without a case/power switch?!
- Why the Radeon 7950 GPU? Why not a 7970, or another video card entirely?
- Why stop at 3 GPUs? Can’t I pack 4-5 (or more) onto one motherboard?
- Can I get PCI-E risers anywhere locally? The ones that are linked in guide ship from Hong Kong.
- Don’t I need more than 4GB of RAM? I read other guides that say I need 1.5GB per GPU, minimum.
- My kill-a-watt shows power consumption spiking up to nearly 900 watts at times, on my 860 watt power supply. Isn’t that bad?
- Can I utilize my mining rig for anything else while it’s mining?
- How much of my internet bandwidth will my mining rig use?
- I’m getting “Error -5: Enqueueing kernel onto command queue.” when running cgminer. How do I fix this?
- I’m getting an error complaining about “libjansson.so.4” on linux. What do I do?
- Cgminer is complaining about a missing shared library file: libudev.so.1. What now?
- I have another brand of 7950 video card. Do you know what cgminer settings to use?
Other
Answers
So how much money can I expect to make from mining, exactly?
This is the question that most people are interested in. The answer is fairly complicated, and changes daily.
Today, one litecoin is worth just over $4. A few weeks ago, that same litecoin peaked at a value of just over $6. A month before that, litecoins were trading at 6 cents apiece. The volatility in digital currency value is extreme—the price today could be very different than the price tomorrow.
On top of that, the difficulty involved with mining a coin is also changing constantly. Today, the rig in our guide will produce about 5 litecoins a day. A month ago, it would have produced ~20/day. The more people mining, the more time/computing power it takes to produce a coin.
You can answer the question for right now by using a calculator such as this one. If you’re building the exact rig outlined in the guide, plug in 1900 in the box next to “scrypt”, make sure that “kH/sec” is selected, plug in 800 for “power” (or 700 if you plan to undervolt), and then plug in your electricity rate. Make sure that the time period you’re interested in is selected (day, week, month). The calculator takes into account the current mining difficulty.
At the time of this writing, assuming you pay $0.08 per kWh for electricity, the calculator would tell you that you should expect to make about $580 per month from your mining rig. Remember to subtract 1-2 percent for your mining pool’s fee. Taking off another couple percent for downtime and other unexpected issues is probably a good idea, too.
If the price of litecoins rises faster than the mining difficulty increases, then that profit figure will increase. If the mining difficulty outpaces the value growth of litecoin (and/or litecoin drops in value), then profit will decrease.
Since it is very difficult to predict the future, I’d strongly advise everyone reading this to treat mining as a hobby, and not a “get rich quick” scheme. Only invest what you’re comfortable losing, because losing is a very real possibility.
Why not just buy litecoins (or bitcoins) directly, and then sell them later at a profit?
If you believe that litecoins are about to shoot up in value, and you have a very high tolerance for risk, and you have some money that you won’t miss if it suddenly disappears, then this might be the best idea for you. Buying the digital currency directly enables you to get your hands on a bunch of it quickly, without having to wait for a mining rig to produce it for you. However, the “sell them later at a profit” part doesn’t always work out. =)
For most of us with a desire to jump into cryptocurrency, mining is probably the safer option. If you buy $1500 worth of litecoins today, and tomorrow they become worthless (and never recover), then you’ve lost $1500. If you purchase a $1500 mining rig today, and tomorrow litecoins are worthless, then you still have $1500 worth of hardware. You can sell it at a small loss, or re-purpose it (maybe try your luck at mining one of the other digital currencies, for example).
This is difficult to answer because it’s so subjective. I will say that an open-air mining rig with three AMD 7950 GPUs in it will certainly not be “quiet”. If you’re planning to occupy the same space as your rig, you may very well find the noise unpleasant. I’d suggest in that case that you purchase the Sapphire Vapor-X brand of 7950, as they are significantly less noisy than most brands.
The heat that a rig produces may be more of an issue, depending on where you live. I live in the northeast US, and in the winter, my rigs double as space heaters—I can easily heat a small room with one. In the summer, the extra heat is a nuisance.
Ideally, you have someplace that you can tuck your rig(s) where they’re out of earshot. Basements and garages are both good ideas if they’re relatively clean and temperatures don’t venture into extremes.
How do I convince my significant other that building a rig is a good idea?
You’re on your own with that one. Good luck! =)
How do I turn my computer on without a case/power switch?!
So you didn’t opt to purchase a power switch, and now you’re sitting there staring at a bunch of assembled hardware, and wondering how the heck to turn the thing on for the first time. Don’t worry, you have a couple options.
If you bought the motherboard from our guide, then there is a power button built right onto the motherboard. This is increasingly common these days, so even if you have another motherboard, check to see if there is a built-in switch.
If you don’t have a button on your motherboard, then grab a flathead screwdriver. Now use the head of your screwdriver to temporarily short the two pins on the motherboard that the power switch would be connected to (if you had a power switch). Just touch the head of the screwdriver so that it makes contact with both pins for a brief moment. Your system should immediately power on.
The first thing you should do at this point is enter the BIOS and change the power options to set your computer to automatically power on whenever power is restored. That way, you can use the switch on your power supply to turn it on and off going forward.
Why the Radeon 7950 GPU? Why not a 7970, or another video card entirely?
The AMD 7950 GPU is currently gives the best hashrate/watt ratio, and also has an excellent hashrate/purchase price ratio. It’s really the ideal GPU for mining, at least for now.
The 7970 does give (slightly) better overall hashrates, but it consumes more power, and costs significantly more. The 7850 is a nice budget option from a purchase price standpoint, but it’s significantly less powerful than the 7950, and it’s hashrate/watt ratio is worse, too.
Nvidia GPUs are out entirely, as they’re just terrible for mining.
Why stop at 3 GPUs? Can’t I pack 4-5 (or more) onto one motherboard?
I like the way you think!
Yes, it is certainly possible to cram 4, 5, even 6 or more GPUs onto a single motherboard. You can actually make use of the 1x PCI-E slots on your motherboard to connect additional GPUs via 1x to 16x riser cables (you wouldn’t do this for gaming or other applications, but mining performance won’t be impacted at all by using a 1x PCI-E slot).
There are some things to be aware of, though.
First, if you plan to go beyond 3 GPUs, you’ll need to use powered PCE-E risers (something like this). Each 7950 GPU will draw 75 watts from the motherboard (and the remaining from the PCI-E power connectors to your power supply). Asking a motherboard to deliver 75 watts for more than 3 GPUs is very likely asking too much—you risk a fried motherboard if you use unpowered risers (like the ones in our guide) for more than 3 video cards. You can also use one of these to supply additional power to your motherboard for a 4th GPU, but you give up a PCI-E slot to do so.
Second, 4 GPUs is the limit in Windows. You’ll run into all sorts of strange issues if you try to add more than that. You’ll need to use Linux if you want to pack 5+ GPUs into a single system.
Finally, you’ll need a bigger power supply. For each additional GPU, add another ~200 watts onto the PSUs rating.
The rig in our guide can easily be expanded accommodate a 4th 7950 GPU by upgrading the PSU and either using one powered 1x to 16x riser or an unpowered riser and an EVGA Power Boost. You may also want to get a larger 6-gallon crate if you’re planning to run a 4+ GPU rig.
Can I get PCI-E risers anywhere locally? The ones that are linked in guide ship from Hong Kong.
Updated 5/8: The guide has been updated to link to fairly cheap risers available on Amazon. If you’re buying in bulk, eBay might still be slightly cheaper.
I haven’t been able to find any risers outside of Hong Kong or China for reasonable prices. I ordered a set from a Boston-based business, but they still shipped from Asia. Ebay is probably your best bet, here. The ones I ordered arrived in about 10 days, and they were decently high-quality (well made with locking clips on both ends). The eBay seller that I purchased from is linked to in the hardware guide.
You can run your GPUs directly off the motherboard while you’re waiting for your risers to arrive by setting up a box fan to blow air between them. They’ll still run pretty hot, though.
Don’t I need more than 4GB of RAM? I read other guides that say I need 1.5GB per GPU, minimum.
Cgminer uses the memory on your GPUs, so you don’t need much system memory at all. You can get by just fine with 1-2GB of RAM in Linux, and 4GB is plenty in Windows.
If you read other guides telling you that you need a ton of system RAM, the author was probably running Reaper as their mining software, which oddly uses system memory.
My kill-a-watt shows power consumption spiking up to nearly 900 watts at times, on my 860 watt power supply. Isn’t that bad?
If you’re not undervolting, but you are overclocking, then it’s possible that you’ll see power consumption numbers this high (or even higher), depending on how efficient your PSU is.
The number that your kill-a-watt shows you is the “at the wall” power consumption—basically, how much electricity you’re actually using.
The number that power supplies are rated for is how much they’re capable of delivering to your system components. This number is after accounting for efficiency loss. For example, the Seasonic PSU that I recommend delivers 860 watts and is 93% efficient (which is excellent). That means that when it is delivering 100% of it’s rated power, it will actually be pulling 925 watts at the wall (860w / .93). High-quality PSUs are typically capable of delivering more than their rated power without issues, as well.
This is why it’s so important to buy a high-quality power supply for a computer that is going to be running 24/7, especially if electricity is particularly expensive in your area. An 80% efficient PSU would pull 1075 watts at the wall when delivering 860 watts to a computer—a full 150 watts more than the 93% efficient Seasonic!
Can I utilize my mining rig for anything else while it’s mining?
It’ll make a great space heater in the winter. =) Oh, you mean application-wise.
The CPU, memory, and disk will mostly be unused while your rig is mining, but anything GUI-related will be pretty unresponsive. Applications that run in the background or over the network are good candidates, if you’re looking to get some extra use out of your rig. You should be able to run things like file servers and low-traffic web servers just fine without impacting mining performance.
How much of my internet bandwidth will my mining rig use?
Not much at all. Mine averages around 30 kb/sec when it’s mining at full speed, which is less than half of one percent of the average broadband speed in the US (~6.6 mb/sec). Bandwidth is basically a non-issue—you could run a mining rig off a dial-up connection.
I’m getting “Error -5: Enqueueing kernel onto command queue.” when running cgminer. How do I fix this?
You’re probably running a 32-bit OS (I highly recommend using a 64-bit OS for mining if it all possible). At least, that’s the only time I’ve seen this error pop up. Try changing your cgminer startup script to these parameters:
cgminer --scrypt -I 13 -g 2 -w 256 -v 1 --thread-concurrency 8192 -o [POOL] -u [USERNAME] -p [PASSWORD]You may not hit quite the same performance level as you would using the settings I give in my optimization guide, but hopefully this will get you running. If it doesn’t, try also installing the latest Catalyst driver & SDK.
I’m getting an error complaining about “libjansson.so.4” on linux. What do I do?
If you’ve followed my guide exactly, you shouldn’t run into this issue. However, if you’re running a different distro, or another version of Xubuntu, it’s possible that you might encounter this.
To resolve, simply enter this on the command line:
ln -s /usr/local/lib/libjansson.so.4 /usr/lib/libjansson.so.4Cgminer is complaining about a missing shared library file: libudev.so.1. What now?
If you downloaded a more recent version of cgminer than the one that I linked in my guide, this issue might affect you. The error message you’ll see looks something like “error while loading shared libraries: libudev.so.1: cannot open shared object file: No such file or directory.” To resolve this issue, you’ll need to run the following command:
sudo ln -s /lib/x86_64-linux-gnu/libudev.so.0 /lib/x86_64-linux-gnu/libudev.so.1If that doesn’t work for you, try this:
sudo ln -s /lib/x86_64-linux-gnu/libudev.so.0.13.0 /lib/x86_64-linux-gnu/libudev.so.1I have another brand of 7950 video card. Do you know what cgminer settings to use?
If you have a Gigabyte WF3 7950, make these substitutions in your cgminer startup script when following my optimization guide (leave everything else the same):
--thread-concurrency 25984 --gpu-engine 1065 --gpu-memclock 1500
If you have a Sapphire Vapor-X 7950, make these substitutions in your cgminer startup script when following my optimization guide (leave everything else the same):
--thread-concurrency 24000 --gpu-engine 1095 --gpu-memclock 1250
If you also follow my undervolting guide, you can use 1037 mV in place of the 1081 mV I recommend on the Sapphire card (and possibly go even lower, but 1037 has always been stable for me).
If you have another brand and are looking for settings, I recommend the bitcointalk forums or the litecoinmining subreddit.
Can I buy you a beer? Your mining guide has been a huge help!
Certainly! Well, virtually, anyway. I’d be happy to accept donations at the below wallet addresses:
Bitcoin: 1DpnANRtMDPe8jG3FXfkyczLFevM94Yjxv
Litecoin: LPuwBa3LbZZzcJaR3kEsGDBivAoc64fPUr
And thanks! =)
Posted in 
Or would it be possible to go headless before installing the Graphics drivers?
Thanks for the great guide.
As you know the optimal GPUs (280) are impossible to find. I am attempting to find alternate GPU but am having trouble with the comparisons. Some GPU describe specifications in terms of CUDA Cores, Core Clock and Boost Clock. While others describe Stream Processors and Effective Memory Clock.
What specifications mean the most to cgminer in gauging “bang for the buck”? Are there any minimums I want to be aware of?
Hi All,
I have been mining for almost a week now, using the “Cryptobadger” rig.
( Thanks Crypto, as soon as I get a payout I will add to your “Beer” fund )
My hash rates are stable at: Card 0 = 640KH/s ; Card 1 = 640 KH/s ; Card 2 = 340 KH/s.
I have tried several adjustments to Card 2 but can never get more than the 300 KH/s.
My pool gives me an average of about 1480 KH/s over the week.
However, I have noticed that my “reward” is falling.
Earlier in the week I was earning about LTC 0.50 /day, now I am down to just below LTC 0.40 /day.
Any ideas what causes these fluctuations ??
Fluctuations are due to increasing difficulty.
In other words: Overall Litecoin Hash rate is going up while the payout is constant.
Expect this to continue.
Expect your payouts fall.
My payouts are down about 70% in 3 months. (Which is fine because the value of the coins have gone up way more than that… )
Thanks, Frodo.
I was thinking that it might be something like that.
I am however quite surprised by the rapidity of the fall-off.
Maybe my case cannot be seen as any kind of average, but I’m effectively down 20% over the course of one week, and the LTC price has stayed all but stable at around US$ 24.
Initially I was expecting to recoup the price of my rig over 3 months or so, but I expect that now to get closer to the 6 months mark.
You can look at the difficulty rate here:
http://bitcoinwisdom.com/litecoin/difficulty
There seems to be some economic realities facing crypto coins right now. Profitability is very high.
In other words, the delta between cost of mining (electricity & HW) and price of the coins is high. As long as this is true, capacity will aggressively be added to the network until the delta is lowered.
The side effect of this is personal risk…
Hi Frodo,
That is a really interesting link, thanks for posting that.
I am mining primarily for fun, but also to get some insight into what cryptocurencies actually are, and how to use them.
If I can recoup my outlay on the hardware and get educated at the same time, then I will have achieved my primary goal.
If I get convinced as to their long-term sustainability, then I might incorporate some Bitcoin/Litecoin into my “retirement-fund”.
I appreciate your contribution to my “education”, thanks again 🙂
Hi, I just bought a desktop with Amd r9 270x graphics card. If I want to add another one to do mining, does that have to be the same brand and style or I can use a amd 7850 or 7950. Thanks in advance.
you can use different card, but then you can’t use the same instance of cgminer/bfgminer, i.e. mixing cards won’t work (well) with same miner instance (though in theory possible).
as always, make sure your PSU can support 2 cards.
By the way, Thanks for a great tutorial. Its a life saving!
I’m running Ubuntu 12.04, 1200watt psu. 3- 280x’s
Just transferred my rig into a milk crate setup from a tower. The only thing I did different was add risers to the 3 asus r9 280x’s, and now the system runs but won’t give me video feed with all 3 cards powered on. When I unplug one card it works fine. Any ideas ?? Everything worked fine when it was in the tower setup.
Wondering if it is possible to mine for more than one type of coin at a time on the same system?
I have heard of people mining LTC with GPUs and another altcoin with the CPU on the same system. No idea how though.
If you want to mine different coin types on the same rig, you’ll need to put your gpu’s into different cgminer/bfgminer instances, assuming you have more than 1 gpu in your rig. i do it all the time, since i mixed 270x’s and 280x’s, and need separate miner instances anyways.
the 2 bfgminer instances also makes using the api extra fun. have to set up separate api-ports for each miner instance, but that’s another topic…
Is there an upper limit to the number of graphics cards that can be run in the system? I know there is a physical limit to the number of slots, however through different riser and splitter cards, you could technically branch out each of the 38 PCI-E lanes to a x1 connection, and thus a separate graphics card. Would this work from a software standpoint though? can linux support that many cards? if not, would it support 16? 10? would the miner software be able to detect/use all of the cards?
But why would you want to put so many cards in one rig?
one PSU failure and your hashrate goes down to zero!
PSU Failure isnt an issue i’m really concerned with. I would spread the load from the graphics cards across multiple power supplies, so one failure shouldnt effect the whole setup. even if it goes down, i’d just go home and replace the power supply. a downtime of an hour or two wouldnt really effect me that much in the long run.
Has anybody had any experience with this ??
What can you do if your pool does not pay out ?
I have been mining for 2 weeks and in the pool I have “earned” 6 LTC so far, but the auto-payout threshold that I set at ( 5LTC ) has been expired, and I have received no response from my pool operator.
What would be the polite length of time to get a reply from your pool on such an issue, I know that some confirmation time is necessary etc. so I don’t want to be too pushy.
.. but how long should I wait before I get that feeling of being “ripped off” ?
-J
there is usually a way to manually cash out. if do , do that asap, THEN maybe switch pools….
Tried that, Anon.
requested manual payout, but no response.
Also sent email to support:- No response.
I have switched pool, but I am still feeling a bit nervous about my payout.
Is my first two weeks worth on mining up the Suwannee ?
-J
WARNING !!!
As I posted above, I am having a problem getting my mining payout.
My pool was Litepool.eu.
I have researched this and found several other miners with the same issue.
( http://www.reddit.com/r/litepool )
The site is still up-and-running, but the manual payout tab has been removed.
It seems that several miners have not received their payout.
I would strongly recommend miners to stay away from this pool.
Maybe they are having technical issues, but some miners are still waiting for payout after 3 months, some being owed up to 25 LTC
I have tried the suggestion above for the libudev on a sapphire but have not had luck with either. Should I be running this in the cgminer dir or the home?
the message i get is failed to create symbolic link /lib/x86_64-linux-gnu/libudev.so.1 :file exists.
Any suggestions?
Like so many others, I got hit by the libudev issue. In a stroke of brilliance, I managed to delete (aka unlink) the original file and couldn’t re-install using apt-get.
I finally found this page, with a nice link to download and then re-install the package:
http://ubuntuforums.org/showthread.php?t=2132483
The 64bit link address is this:
http://mirror.pnl.gov/ubuntu//pool/main/u/udev/libudev0_175-0ubuntu13_amd64.deb
Use wget from your miner to put that in your home directory, then use:
sudo dpkg -i *.deb
(Assuming that’s the only .deb file there, otherwise specify the file.) dpkg will place the bits where they need to be in your system.
hi guys,
i have some trouble with just one machine. it is an c2d with enoug ram etc.
i installed everything ad described here. everything works except cgminer.
with “./cgminer -n” i get:
./cgminer: /lib/x86_64-linux-gnu/libudev.so.1: no version information available (required by ./cgminer)
I tried installing ubuntu 12.04 xubuntu 12.10 and 12.04 BUT ALL ARE GIVING THE SAME ERROR……. I am getting crazy here. the same machine works fine with windows but i want Linux.
this error makes that cgminer starts…… and stops. when I hit q it does stop (the proces) and i get some results (hash about 6) but this is not working and all the results are rejected….
your thougts please!!!
Stamper,
I had the same problem.
I fixed it by downloading the latest libudev-dev package.
try :
sudo apt-get install libudev-dev
thanks. got more errors but cg miner works!!!! and that is all that counts!!!
Cryptobadger,
I don’t know if you still actively watch what is going on in your pages here, but I have a thought for you.
You now have several followers here, and it would be great to see some kind of summary of our communal efforts.
Would you like to maybe create a page where we can all upload the results from our rigs ?
Things like:
–Type of GPU’s
–settings in cgminer script.
–Hash rate results
( PS I still owe you a beer, I was hoping to get you one sooner, but the pool I joined failed to pay out, so my LTC wallet was empty until today ! ( Yippee ! )
after 4 weeks mining I now own 1.311 LTC !! )
Has anyone used these risers with R 290x sappphires?
USB 3.0 Powered PCI-E PCI Express 1x to 16x Risers 60cm
Thanks
man, i would REALLY stay away from usb3 powering.. to me , it seems the power specs are lower / or more regulated; even some mice and keyboards dont always seem to power up with 3.0 all the time.
They’re not USB-powered, they just use that for communication. They’re powered by PSU to SATA pins I think. In any case, they have to be powered from the peripheral plugs on the PSU.
60cm!? :-O
I’ve ordered 8 version 1 from Alibaba and 2 version 2 from eBay. When they arrive I’ll see how they work out.
My (20cm) risers finally turned up after about a 6 week wait…I ordered the wrong ones!! – have sold them on eBay and ordered the right ones which should be here within a week. Standard non-powered ones.
Let us know how you get on with these bad boys though!
I followed your Linux install instructions to the letter and I just cannot get cgminer to run. I get this error every time (and I’ve done 5 Xubuntu reinstalls, 2 of which didn’t work properly):
“error while loading shared libraries: libudev.so.0: cannot open shared object file: No such file or directory”
Your instructions refer to a problem with the libudev.so.1 file, not the libudev.so.0 file so I’ve no idea how to fix this issue.
Also, your install instructions refer to an old 2.11 version of cgminer (I did try to install that version). Since 3.7.2 is the last edition that supports scrypt, could you add upgrade instructions for those of us not familiar with Linux. There’s no built version of 3.7.2 available and no instructions on how to compile that version either.
I’ve spent 5 days now trying to get cgminer to run on Xubuntu. Very frustrated.
Can anyone reading this provide any advice/solutions?
Thanks.
seen that to. i was so lucky to have one downloaded at my nas. you could have it if you like.
go the windows route. WAY easier.
With the help of these guides (and few other resources) I have finally built a decent rig (in my opinion) which is churning around 1+ MHS (with two 7950 cards) and is stable so far (TouchWood …).
I will be adding 1 more card as and when I find a good deal (craigslist/ebay).
Now the next question: Which mining pool to go with.
I’ve started with HashFaster.com with CoinOTron as fail-over.
Based on your experience, can you suggest me a mining pool(s) for around 1.5 MHS hashing power, that gives a best bang for my rig.
Thanks once again.
Stay clear of :
Litepool.eu !!!
-J
( see my earlier post on this )
i’ve been mining at give-me-coins.com for ltc and ftc, and their “sister” site(couple of mods from GMC irc) united-miners.com for several other alt coins.
both sites have great support, and honest operators. never a problem with getting paid.
I used the Windows OS and all the hardware as recommended here at Cryptobadger. However, my system does not recognized TWO of my GPUs (I’m trying to run 4) and, of the two it recognizes, it believes that one is a 6950. This is not true. All four are Gigabyte AMD Radeon 7950s. All four GPUs are fine. No matter which two I put in, they all work, but always one is recognized by the motherboard/operating system (not sure which) as a 6950.
What do I do? Uninstall everything and reinstall? I would think that the solution is somewhere in the BIOS but no sign of GPUs in the ASRock Extreme 4 mobo setup pages.
How do I get 4 GPUs running??
Chris.
Did you try the AMD system monitor and see what it says..
(http://support.amd.com/en-us/kb-articles/Pages/AMDSystemMonitor.aspx)
Is it worth to get into this with just one Radeon 7950 GPU and then build into the other three?
gotta start somewhere, and a 7950 is a GREAT starting point. i’ve seen(or provided support to) a lot of other guys starting off with some old crappy nvidia card, and when they realize its not worth the electricity to run it, they either quit mining or upgrade to ATI cards.
go nuts! get that bad boy hashing.
Thanks, I ordered the MB/CPU/Ram. Next pay check is the 7950.
just keep in mind a single 7950 might only earn you around $4/day…
CORSAIR HX850 850W 80 PLUS GOLD
3 x PowerColor AX7850 2G
G.SKILL Ripjaws Series 8GB (2 x 4GB)
AMD FX-6300 Vishera 3.5GHz
usb thumb stick with xubuntu
I had this rig up and going smoothly for a long while. Then I decided to add 2 more 7850s. I used powered pci 1x risers for the 2 extra cards. At first the rig would make this kind of squeak/beep noise then power off right away, in about 1 second. I unplugged one of the cards and then it would appear to boot up, all fans would start spinning. I tested the card with the other powered pci riser and the same thing would happen. I tried the same card and riser in the slot that the other powered riser was in and the same happened. So I figure that one of the powered risers are faulty. So I just plugged in 4 cards with the 4th gpu using the good powered riser. Tried to boot up, all fans would start spinning but the PSU fan would stop after about 5-10 seconds. The network adapter light wouldn’t light up. Removed the 4th card and tried again, same thing happened. So now I’m back to my original setup and all fans start but the psu fan stops after 5-10 seconds. Network adapter not lighting up. Hooked up a monitor and got no display. Any one have any idea whats going on?
You are killing your power supply. A quick google search tells me that a 7850 consumes about 125W. I would actually expect a bit more. I am having trouble deciphering whether you have 4 or 5 cards total. In any case, keep in mind that the rest of your system needs power also. Furthermore you want to have some margin rather than maxing out the capacity of the power supply.
tl;dr You probably need a more powerful PSU, or an additional PSU. It isn’t the riser’s fault.
It won’t even boot with just 3 cards now. One of the risers are definitely faulty. If I have the bad riser plugged in at all, nothing will power up at all. With the good riser plugged in, all fans will spin up. But like I said, even when I revert back to my original setup with just 3 cards, all fans get going but the PSU fan stops after about 5-10 seconds. No display, nothing.
You may have a bad riser but it really sounds like you fried something… probably the power supply.
5 x 125W = 625W
850W – 625W = 225W for everything except video cards
That assumes that the power supply really can supply 850W constantly and that your video cards never draw more than 125W each. My system draws over 200W idle.
I’m pretty certain you overwhelmed your power supply. But it’s also possible that your motherboard’s power circuitry was stressed/damaged if you had too many video cards trying to pull power from it. Sounds like a malfunctioning powered riser could have caused that to happen?
Try dropping down to 1 video card in the system and see if it powers on. Also your motherboard should produce a beep pattern of some sort to indicate what might be wrong. Consult the motherboard manual to determine what it means. If it does not have an on-board speaker, make sure the case speaker is hooked up.
I don’t have a speaker fan handy. I definitely think your right about the PSU or mobo frying. I hope it’s the PSU because I can still RMA it.
So I found a case speaker plugged it in. Just plugged in RAM, CPU and GPU. Double checked connections. On power up the PSU fan starts for a few seconds then stops. The CPU and GPU fan continue to run. No beeps, no display.
I had 3 cards, was trying to add 2 more
Hey.
I follow your tuto and built my own rig. Thx for you help. No I am facing a problem.
First, my config
Motherboard ASRock 970 Extreme4
Processor AMD Sempron 145
Memory 4GB G.SKILL DDR3 SDRAM (2 x 2GB)
Power Supply corsair 860w Platinum PSU
GPUs : 2 Sapphire HD 7950 3GB GDDR5 plugged in pcie 16x.
I don’t use any riser.
My rig crashed a week ago. When I tried to reboot it, it was impossible. Nothing happend (no light, no fan, nothing). After several tries, I understood that if one of the two GPUs (lets say “GPU2”, the one which was in the slot 5) was connected to the PSU, my mobo could’nt start. I tried to put it in the other pci-e slots, but nothing happend, unless I unplegged it to the PSU. GPU1 worked everywhere.
As it was a new GPU, I had it exchange at my store. Yesterday, same thing happend. I also noticed that if only one of the two power plugs of my GPU2 is plugged to the PSU (the left one when you face the fans), the mobo starts, the fans of GPU2 works, but the card is -and this is normal -not detected by the computer.
Do you have any idea what happend ? Is my GPU dead ? It is a short ?
Thx.
me too i have a similar issue with the Sapphire 7950 dual x.
i checked the power connector on the GPU and found a short between the +12v and common in two pins.
i didn’t use PC i risers but i plugged one in 1×16 and the other in 1×8.
this is the second card from sapphire that got busted in my rig after running about a week of working continually. i don’t know if this is a common problem but we might need to stay away from these cards, otherwise, i might be doing something wrong which i can’t see what it could be.
i didn’t set a high difficulty, only about 17 and got a 520 kh/s my temps measured by cgminer didn’t go above 76.
i would appreciate any thoughts on this issue.
Thanks
Hello,
Need some help…
This is my setup:
OS window 8.1 64bit
RAM 8GB
4 x Sapphire R9 290x
MSI Z87-G45 Mother board
2 x 1200W cool master PSU
When I have the system running with 3 cards it boots up fine and works ok with any combination of cards. As soon as I add a 4th card then the system fails to boot up or sometimes boots up and cgminer crashes after 5mins. Also when it fails to boot up the fan on the 4th gpu starts spinning very fast this can be any of the GPU. I have replaced the powered PCI riser cable and still have the same problem. I have 2 GPU’s on the Mobo and 2 GPU’s using powered pcie riser. 3 GPU’s are powered from 1 PSU and the 4th is powered from the second. I am using a PSU slave cable to get the second psu to come on at the same time as the first. I managed to get the 4 gpus to work for about 48hrs and then have been having these problems.
Thanks for your help and I look forward to any information i can get on this as I am building up the rig to 6 cards gradually and this is currently a stumbling block!
Thanks
My pool has not found a block for over 14 days now.
With the current difficulty at about 5.600 is this the new normal, or are we just having exceedingly bad luck ???
The combined hashing power of the pool is currently at about 80MHs/s, that’s down about 20% from what we were doing last month because I fear that pool members are leaving to go elsewhere.
As things stand, my 3 x 7950 card rig is using more electricity than I am making in coin right now.
Any thoughts from you guys on this ?
Why not join a bigger pool? Is this a pool that you run? Larger pools reduce variance so you don’t go two weeks without getting paid. You can also consider alt coin mining as it tends to be more profitable than ltc.
Hi Greg,
No, i do not run the pool,and joining a bigger pool would be my next step.
i understand the variance is smaller in bigger pools.
I just wanted to know if other pools are still finding blocks at regular intervals, and although I expect a drop in payout frequency as the mining difficulty increases, 14 days without finding a block seems to me more than just bad luck.
If I break from my pool now then I will lose the shares that I have put in over the last 14 days. I also want to stay with LTC mining as it is more widely accepted than other coins.
Consider a multi-pool that switches to the currently-most-profitable coin on the fly and automatically trades for BTC or LTC. Or you can mine whatever you want on your own and take advantage of something like Cryptsy’s auto-trade feature, but that costs an extra 0.1% I think. Or just go to a bigger litecoin pool. But yeah, it’s not just bad luck. Because there’s no such thing. It’s probability. With only 80MH/s total your pool may never find a block, making your shares worth about as much as Mt. Gox bitcoins. The new ASIC miners that are coming out each produce about 3x the hashrate of your entire pool. Overall GPU mining is becoming rather unprofitable. 🙁
When trying to execute ./cgminer -n, I keep getting this error:
-bash: ./cgminer: cannot execute binary file: Exec format error
Any ideas?
Which version of xubuntu are you using?