thinking of building a bitcoin rig...

[dpk33]

I have a few questions about doing this.

1. What is a good motherboard with many pci-e x16 slots? preferably 2 or more. am3, am2+, 775, doesnt matter. I'm going to be running it caseless, probably going to put it on the ground. Good idea? Bad? What's a good surface for this?

2. What is an efficient gpu for bitcoin mining? I was thinking a 6850 or 6870.

3. What is a good and efficient power supply for powering 2 or 3 of said gpus above?

4. I heard they crashed a few months back, but they're regaining their popularity and value. Is this true?

5. Also is it possible to use two or more different gpus for mining? e.g. I have a 5770 and 2 5850s. Can I use all 3 in one system and have them mine that way?

 

[Vesku]

My suggestion:
Get one of the 6850s or 6870s that are on sale with rebates or a used 5770/58xx card if you prefer. Put that in your secondary PCIe x16 slot (that's just for convenience Bitcoin can be done from even a PCIe x1 slot if you can fit the video card in one). Go to bitcointalk.org and read up on mining software and mining pools, I use GPUMiner atm. I think with something like Bitcoin it's best to put a toe in the water before getting your feet wet.

 

[WhoBeDaPlaya]

Generally, the cheapest possible setup is the AM3 platform.

1) Look out for ATX Biostar AM3 mobos. They went on sale for as low as ~$40 after rebate late last year.
I use A870U3s in all my dedicated miners in normal ATX cases with dual 5830s. I like a clean setup and
prefer not to use PCI-E risers, otherwise you should be able to cram 3x cards into this mobo with 1 riser.

2) 5xxx are the most efficient. That said, a 6870 or 6950 could work very well IF you get them cheap enough.
eg. I got several 6950s for ~$130 each. At the time (months before the 7970 release), it seemed a much
less risky investment than more 5830s (ie. if GCN turned out to be fantastic at mining, resale on the 5830s
would be f*cked, whereas people would still buy the 6950s for gaming).

3) Don't get caught up in fancy PSUs. I'm not saying to go el cheapo either, although if you keep your eyes
peeled, you can find good, solid PSUs for cheap (usually the Corsair 430CX, 500CX, 600X and the Enermax
clone EN-600AWT). This is another reason why I limited myself to dual-card miners - PSUs get mighty pricy
once you start exceeding 600W.

4) BTC didn't really crash IMHO - well sorta (if you were expecting $60/BTC). They stabilized at ~$2/BTC for
months and there was a stable cycle every couple of weeks where it would rise to ~$3.20/BTC. Still enough
to be profitable if you had already invested in mining infrastructure.

5) Never tried this, but IINM it's possible since you don't run them in crossfire or anything.


HTH! Here are my A870U3s : http://www.youtube.com/watch?v=VLHwaroZZkk

Just for the hell of it, I added USB speakers to all my miners - nice notification when they sucessfully startup / shutdown :

Startup : http://www.youtube.com/watch?v=tXPFLplE0Ns
Shutdown : http://www.youtube.com/watch?v=JSC-XPM5HsY

 

[WhoBeDaPlaya]

...

 

[superjim]

You already have some of the best GPUs for mining, the 58xx series. Keep your 5850s for the bitcoin rig. Cardboard is always a good surface, non-conductive and with some duct tape is fairly strong if you wanted to make a container for it, punch some holes, etc. For the power supply, make sure to get at least an 80 plus Bronze certified, preferably Silver or Gold so you're wasting the least amount of power as possible. As Playa pointed out, you don't need to get too fancy and stick with the minimum wattage you can use for the 5850s. Some miners go as far as to under-volt the CPU to save a little more power. AM3 rigs are generally cheaper than Sandy Bridge rigs, last I checked anyway.

 

[Vesku]

Ah, missed the "I have a 5770 and 2 5850s. Can I use all 3 in one system and have them mine that way? " bit.

Put a 5850 in your other PCIEx16 slot and try out mining on a pool. If after a trial run you want to get some use out of your other 5000 series cards, I would find the cheapest cpu+mobo combo that has 2 or more physical x16 slots and run the other 5850 and 5770 in that.

 

[Madpacket]

Mining is a good way to make a few bucks but unless you invest heavily, don't expect to make a living off it. You have excellent and efficient cards already, I would spread the cards over two systems for simplicity but you can run 4+ cards off one system but it's tricky to setup. Also try and dual purpose the mining machines. For example I mine around 950mh/s with only my media center and gaming pc with one card in each machine. Both have primary uses but they also always mine. You can set the GPU priority of the miners to be lower than your primary tasks so as to be able to watch movies and still game, this works really well with cg miner.

Anyway good luck and read the dedicated forums for help.