Building a 6990 rack

[jothan]

Hello all,

My mining rig has now been in operation for 2 continuous weeks. By fiddling around, I have noticed that my 6990's require proper airflow on both sides (fan input and backplate). I am thinking of getting cablesaurus adapters (1x to 16x with power) to be able to move the cards apart and build "rack" to hold the GPUs. I currently have 2 cards, but allowing the possibility of 3 or 4 would be nice.

I was wondering if you guys have any tips on securing the cards or have suggestions concerning materials, best distance between the cards, general rack layout, etc...

I am also thinking of getting a clothes dryer pipe to be able to bring in outside air. I am concerned about condensation, so if you guys have any tips, they would be most welcome.

Thanks !

[RyNinDaCleM]

I am thinking of getting cablesaurus adapters (1x to 16x with power) to be able to move the cards apart and build "rack" to hold the GPUs.

I am also thinking of getting a clothes dryer pipe to be able to bring in outside air. I am concerned about condensation, so if you guys have any tips, they would be most welcome.

Thanks !

PCIe risers are very beneficial to your cards. I try to keep a minimum of an inch between cards, but more would be better.

You won't have to worry about condensation. Condensation only happens when a surface is cold then heated.

[tnkflx]

If you're building a 4x ATI6990 rack, take care of the following:

- The ATI 6990 pushes hot air out on the front and the back of the card. If you're using a closed case, make sure you can exhaust all the hot air as this card will also be blowing hot air IN the case. I'm using an open frame.
- I opted to use 2 linked PSUs.
- I also used PCIe risers with an extra 12V rail.
- Make sure your motherboard actually supports 8 GPUs. I had to disable various internal components (USB3 controllers, eSATA, etc...) before it would even start, there were not enough BIOS resources available to start all these things and the 8 GPUs together.

[kibblesnbits]

PCIe risers are very beneficial to your cards. I try to keep a minimum of an inch between cards, but more would be better.

You won't have to worry about condensation. Condensation only happens when a surface is cold then heated.
[/quote]

I've seen a few rigs for sale and was wondering which PCIe cables work best.  The rig that was pictured for sale had five video cards that looked like 4x cables attached to each card?  I have a setup now with two 6950s and they are directly plugged into the mobo. 

These are the cables I was looking to get...

http://www.amazon.com/HOTER-Express-Riser-Flexible-Cable/dp/B0057M0LT6/ref=reg_hu-rd_dp_img

[jothan]

If you're building a 4x ATI6990 rack, take care of the following:

- The ATI 6990 pushes hot air out on the front and the back of the card. If you're using a closed case, make sure you can exhaust all the hot air as this card will also be blowing hot air IN the case. I'm using an open frame.
- I opted to use 2 linked PSUs.
- I also used PCIe risers with an extra 12V rail.
- Make sure your motherboard actually supports 8 GPUs. I had to disable various internal components (USB3 controllers, eSATA, etc...) before it would even start, there were not enough BIOS resources available to start all these things and the 8 GPUs together.

(in order)
- Ya, I got a bit caught up with that part with the current case, I did not plan ahead too much on the other stream of hot air exiting the card. Not really a problem with the current case, but could be much better. I am thinking of putting the cards flat (long side parralel) to have the air inputs all pointing in the same direction and pipe cold air right there. I also have to make sure the back gets plenty of air.
- I currently have a 1200W PSU, it is plenty for 2 cards, but I have not taken an empirical reading on the actual watts used by the cards and the rest. From reading the specs, I should plan for about ~350W per card (or is it per GPU ?).
- Yes, I am thinking of buying the 1x to 16x adapters with a 12V molex plug in order to not burn out the cable, the cablesaurus ones seem ideal.
- I don't know if this could be an issue, I use a 64-bit linux operating system and a recent motherboard...

[DeathAndTaxes]

- I currently have a 1200W PSU, it is plenty for 2 cards, but I have not taken an empirical reading on the actual watts used by the cards and the rest. From reading the specs, I should plan for about ~350W per card (or is it per GPU ?).

Don't guestimate anything.  Get a kill-a-watt.  It is a a negligble cost compared to high end PSU and GPU and will allow you to get accurate estimate of electrical load.  For the record your 6990 (if the memory is underclocked) will consume a lot less than 350W.  The oft repeated 350W is TDP which is only a measure of max thermal load the card can displace (before melting, burning, or igniting nearby components).

[tnkflx]

- I currently have a 1200W PSU, it is plenty for 2 cards, but I have not taken an empirical reading on the actual watts used by the cards and the rest. From reading the specs, I should plan for about ~350W per card (or is it per GPU ?).

Don't guestimate anything.  Get a kill-a-watt.  It is a a negligble cost compared to high end PSU and GPU and will allow you to get accurate estimate of electrical load.  For the record your 6990 (if the memory is underclocked) will consume a lot less than 350W.  The oft repeated 350W is TDP which is only a measure of max thermal load the card can displace (before melting, burning, or igniting nearby components).

Meh, I should measure the power usage of my rigs... ;-)

[tnkflx]

If you're building a 4x ATI6990 rack, take care of the following:

- The ATI 6990 pushes hot air out on the front and the back of the card. If you're using a closed case, make sure you can exhaust all the hot air as this card will also be blowing hot air IN the case. I'm using an open frame.
- I opted to use 2 linked PSUs.
- I also used PCIe risers with an extra 12V rail.
- Make sure your motherboard actually supports 8 GPUs. I had to disable various internal components (USB3 controllers, eSATA, etc...) before it would even start, there were not enough BIOS resources available to start all these things and the 8 GPUs together.

(in order)
<snip>
- I don't know if this could be an issue, I use a 64-bit linux operating system and a recent motherboard...

I use Win 7 64-bit and a recent motherboard... If you don't have enough resources with 8GPUs, you don't have enough resources, new motherboard or not