Advice on cards for mining.

[godfreyandthandi]

Hi, im setting up a rig in the coming week or two and was wondering what would benifit me more:
2x 5970's $620 each no warranty or;
2x 6990's $730 each 2 year warranty.
I understand for the 6990 i would have to go from a 1000w to a 1200w psu, and thats only $100 for me.
But also looking at this from a resale point of view, what seems the best deal?
Attached is what i have so far, i like the motherboard because it can support bulldozer for resale, and the 3x pcie slots means good spacing.
http://i55.tinypic.com/30mtqo6.jpg

[psknives]

I suggest getting a better cpu unless you want to get held back and lose performance in mining. Also, I suggest getting 4x pci 2.1 mobo with 5870's or stick with the 5970's or go for the 6990 and stick with the mobo.

[niooron]

I suggest getting a better cpu unless you want to get held back and lose performance in mining. Also, I suggest getting 4x pci 2.1 mobo with 5870's or stick with the 5970's or go for the 6990 and stick with the mobo.

More CPU? A single core Sempron is fine. AMD's OpenCL implementation barely uses the cpu.

[PwrLeveld]

I have heard of people using a sempron for their 4 gpu rigs. I think it will be fine using that setup, but if you are planning on doing any gaming or anything else at all I advise a phenomII x4(or wait for bulldozer but then mining won't be as profitable).

[godfreyandthandi]

i have a seperate gaming pc.
Another option ive been considering is the 5850 twin frozr 2's which i can get for $200 each, would this be at all worth it? i could run 4 off this mobo with a 1x mod?

[PwrLeveld]

4 5850 would proboably netting around the same hash rate but I'm not sure.

[psknives]

I have heard of people using a sempron for their 4 gpu rigs. I think it will be fine using that setup, but if you are planning on doing any gaming or anything else at all I advise a phenomII x4(or wait for bulldozer but then mining won't be as profitable).

Processing power is required to move data around and do instructions, those instructions and data being moved around are done in the GPU... now let us BOTH think what happens when your CPU can't keep up with the GPU in some (i said some) respect? Obviously the GPU is and will always be better, BUT it doesn't mean you put a $10 single core with a $700 GFX and expect perfect results. If your going to do that at least get a duo with 3 ghz or quad with 3 ghz or even a 6 core if you plan to go for the 2x 6990s...

[xenon481]

BUT it doesn't mean you put a $10 single core with a $700 GFX and expect perfect results.

Yes.... It does.....

Keeping the GPUs fully fed takes absolutely minimal CPU power.

[PwrLeveld]

6 cores is completly overkill in linux. Linux will only use 10-13 percent cpu usage per miner thread, so even a dual core @ 2.8 would give no worries. All the cpu does for the most part with the way AMD setup opencl is feed info to the gpu.

[Veldy]

I have heard of people using a sempron for their 4 gpu rigs. I think it will be fine using that setup, but if you are planning on doing any gaming or anything else at all I advise a phenomII x4(or wait for bulldozer but then mining won't be as profitable).

I am guessing that the binary module that Python is using to work with the GPU is either itself going into a busy wait loop at times when trying to get GPU resources or that the Python code itself is.  I haven't looked at it yet, but that sort of thing shouldn't be too hard to mitigate.

I would be careful about building big rigs with funds that you really can't afford [it should be money you are 100% willing to risk losing]. for new people since the market is still a big unknown and quite volatile and while it has done well for the past month, it may go belly up just as easily like many online currencies attempted before [there is still not a single major vendor that will accept bitcoins for payment .... steering clear of tax collectors I am guessing].  Unlike gold, the price of a bitcoin is 100% market based with no value of its own; something it shares with fiat money.  Gold will always have some value.  Money represents resources [i.e. gold, physical labor, food, etc] where gold is itself a resource [it can be traded as money or actually consumed in production of goods].

[Veldy]

BUT it doesn't mean you put a $10 single core with a $700 GFX and expect perfect results.

Yes.... It does.....

Keeping the GPUs fully fed takes absolutely minimal CPU power.

Bus speed is the only issue really and the CPU only cares about moving data and results ... it makes decisions and does no computations [unless you do CPU mining].  CPU requirements for GPU mining are minimal.  The spikes people are seeing in CPU core usage when running multiple GPUs is almost certainly an issue with drivers, the module/library used by Python to work with the GPU computational resource or the Python miner code itself [i.e. a busy polling loop] and in fact, a deficit in the drivers may force the other code to compensate [and thus a busy pooling loop].  We ALL know about ATI's (now AMD's) notorious driver quality.

NOTE:  I indicate Python because the major minors are written in Python at the high level.  Also, I have not looked at the code myself, so I am speculating about the cause of the spikes, but there is no theoretical reason why significant CPU processing power is required.

[unxetas]

Or of course you could use some of that money to send me the copy of steam I paid you for before you blocked me on steam and changed your profile name?

[shat]

In my newest rig, built ignoring power requirements and mainly most hashes for less $ I went 5850 and I get 300Mhash/s ea. I run 2x5850 in each box. Total of three boxes running on our datacenter floor. Total cost was about 340$/each using chassis mobo and CPUs I had. I het 5850s for 129$ from a vendor we do a great deal of volume with each month.

[zoro]

i agree, 3 or 4 5850 in a rig are enough and really cheap
it is the same with 2x5970 (in windows 4 gpus are the max you can get)

[mrb]

Processing power is required to move data around and do instructions, those instructions and data being moved around are done in the GPU... now let us BOTH think what happens when your CPU can't keep up with the GPU in some (i said some) respect? Obviously the GPU is and will always be better, BUT it doesn't mean you put a $10 single core with a $700 GFX and expect perfect results.

Yes, perfect results. All my 4 x 5970 rigs have a low-end single-core $30 Sempron processor and run at exactly the expected speed.

You need to get a sense of the workload involved, and understand numbers reported by your system monitoring tools. We are talking about a few hundred kB/s exchanged on the PCIe links. And the CPU waking up every 100ms or so to send new work items to the GPUs. It is peanuts. All of that is orders of magnitude below what a single Sempron core is capable of.

[dingus]

Or of course you could use some of that money to send me the copy of steam I paid you for before you blocked me on steam and changed your profile name?

[godfreyandthandi]

Or of course you could use some of that money to send me the copy of steam I paid you for before you blocked me on steam and changed your profile name?

Excuse me?

[bolapara]

Indeed, CPU needs are minimal.

I have two 5870's pushing about .825GH/s while running on a 2.6 GHz Celeron in Ubuntu and the CPU is near idle.  15 minute load average is 0.05.

[SgtSpike]

My honest opinion?

Go for mining, not resale value.  If you sell it in the future, part it out, don't sell it as a whole rig.  You'll generally get more for it, especially if you have dual or triple high-end cards in it.  Not many people are willing to pay such a premium for cards they'll never make use of.

With that in mind, I would suggest the following changes:
- 1GB of DDR3 ram, the cheapest you can find.  Should be about $13 shipped.
- 250GB HDD, $39.
- Cheap generic case - just something that works for mounting a motherboard and PSU - $20
- Single core Sempron - $39
- Can't really argue with your choice of PSU - if you need a good one, you need a good one.
- Can't argue with the choice of motherboard.

With those changes, you'd save about $227.  Of course, maybe that's pocket change for you, I don't know.  But that's my suggestion.

Also, check out the link to the spreadsheet in my sig.  It'll help you figure out how much money you can expect to make (or lose) by building a rig and mining with it.  It's the Mine or Invest link.

[unxetas]

Or of course you could use some of that money to send me the copy of steam I paid you for before you blocked me on steam and changed your profile name?

Excuse me?

If you insist - thewhiteman posted a thread selling steam games. I agreed to buy portal 2 for 11btc. The Whiteman added me on steam and we agreed I'd send half first and he'd send me the game as a gift, I'd send the other half afterwards. I sent 6btc and he said he Had just installed bitcoin from a fresh reformat, so the block chain was still building. Whatever.. The hockey game was on so i told him to send the game whenever he saw the transaction.

When I came back hours later, the window was still open but he appeared offline. I clicked on his profile and was redirected to godfreyandthandi's profile - along with a message that the user was blocking me. Classy.. The comments on his profile were the same as before, but he did change the city and state he was in.. Almost untraceable! Lol.

Came back to the forum where I noticed that he had replied to his original thread under this username as well, in response to a price request. Actually there's also at least a third login that he used on the same thread.

Excuse me? Ah.