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Hi guys,

Who here is successfully running a 3 or 4 card 6990 ATI system?

I need some pointers please.

Any 3/4 x 5970 rigs operators may also comment.

All the above. I have 3x5970 rigs, 4x5970 rigs, 3x6990 rigs, etc. What is your pb? Are the install guides you read incomplete?

It's not possible. Windows allows for a maximum of 4 GPUs. The 5970 and 6990 is a dual GPU card.

I guess you've never heard of Linux..

Hey guys,

No I'm just getting really conflicting advice.

Folks tell me stuff like 1200W is the minimum you need to drive a 3 card rig and that standard cooling will not cut it.

It's really expensive equipment and I don't want to go blow something or burn something out or waste time.

In your experience, can you run 4x6990s in one box, can you power it and can you cool it without an electrical engineering degree?

On the linux/windows issue, I'm assuming you can just not use more than 4 GPUs at once but that windows will work fine if you need to boot into it.

Yes.

Buy a powerful quality PSU. Seasonic.

Use a case with 180mm fans, and lots of them, and good ones. Delta. Or no case at all, and fans positioned to feed cool air and suck hot air.

Awesome thanks,

Have you done that successfully or something very similiar?

For 4x5970, I have done it with as low as 1120W of total PSU power (2 x 560W): http://blog.zorinaq.com/?e=42 But don't do this unless you have a clamp-meter for precise measurements, and a highly power-optimized config (low power CPU, diskless, etc).

At stock clocks/voltages, count 275W per 5970 and 346W per 6990 (my measurements). Multiply by how many cards you have. Add some headroom for the rest of the system: 50W minimum. But that's cutting it very close. For most folks I would recommend to count the TDP of each card (294W per 5970, 375W per 6990) and to add 200W headroom for the rest of the system. Or even more for significant overclock/overvolt mods.

Thanks mrb,

what do you mean by clamp-meter, electric multi-meter?

Also, I assume single GPU cards take less power, correct?

http://en.wikipedia.org/wiki/Clamp_meter

Yes

Standard cooling works fine with a large case with good airflow and several fans. Do not put the cards side by side. Make sure there is at least one empty slot between each card.

Not all 1200 watt power supplies can support 3x 6990s. Many will die under the load. We've used both Antec and CoolerMaster 1200 supplies successfully.

Here's what our 3x 6990 rig looks like: http://www.bitcoinrigs.com/product_images/p/257/Rig_2000-inside__88644_zoom.png

That pic is quite inspiring :D
What mother board did you use for that setup? I'm looking at the http://www.msi.com/product/mb/890FXA-GD70.html
Will that cut the mustard?
Also will a Sempron work fine or will it cause some sort of bottleneck?

From what I've read on other threads, that board should do fine. Certainly enough slots available.

What case are you considering?

What kind of a processor would you need for a 3x6990 setup?

Would a Athlon II x2 250 (3ghz dual core) be good?

That proc will be fine.

Nice quick reply, thanks for that.

Hi,
Do you use all the fans in the case? Also how much power do all the fans draw? Or how many watts does the whole rig draw?