Thanks to the help from good folks at:
I am leaning to this being a vram issue. If I get all the parts in time then the plan is to drainthe loop, re-seat the block and move the card to a 16x slot. I have to do this in one shot because draining and refiling this beast is not a trivial affair which is caused by the top mounted radiators. I’m reconsidering going to a bottom radiator configuration.
I will also be adding 3 temperature sensors and 2 flow sensors to the loop which should make debugging temp related issues a little easier.
The flow sensors will be added at the pump exit and at the reservoir entrance which should give me a nice delta readings.
The temp sensors will be added at the pump exit, at the CPU exit, and at the last GPU exit this should be interesting as well.
After putting the system together having a pair of water cooled and crossfired HD 6990s.
I’m getting horrible artifacts in 3D Mark 11. This did not happen with same cards in my previous air cooled setup.
Looks like I erroneously mounted the second HD 6990 in an x8 PCI-E slot instead of the 16x slot. Another possibility is poor vram contacts to the water block. The GPU temps are OK, <50c under full load, not sure about the vram. Next mod is to go to the 3 way bridge and reseat the water block on the second card with fresh thermal tape.
Thinking that placing second HD 6990 in an 8x PCI-E slot instead of 16x slot can cause this artifacting or maybe can this be a vram temperature issue?
I already eliminated drivers from the equation and narrowed it down to one of the cards by using PCI-e switching option of Rampage IV.
Here is the test video. With my prior x58 setup the cards ran without issues. Now on x79 I get this. What else can this be?
I can run MSI Kombustor on extreme setting with Prime95 running 12 threads.
Even running it for hours there are no artifacts and the temps never reach over 50c on either the CPU or any of GPUs.
I will try re-seating the GPU waterblocks this weekend.
Another video: http://youtu.be/l8C8CfHLfpU
Finally got everything together. Still some tidying up left, once I get my Bitfenix Alchemy Multisleeve extension cables should look better. Also in the works are 3 Phobya G1/4 In-line Female to Female Temp Sensors and couple of Koolance Flow Meters with frequency adapters.
Here is a short video of the first boot:
CaseLabs MAC-151 3.5″ Bay Device Adapter and Bitfenix USB 3.0 Front Panel fitted:
Here is what Koolance is saying about running two pumps with serial bypass:
If running in series with the RP-452X2 Rev 1.3, you would want to use the bypass acrylic piece (for best performance). The bypass acrylic piece should be installed into the bottom right reservoir. The connecting pipe should bridge “P1 [IN]” and “P2 [OUT]” (bottom two ports).
If you aren’t using the bypass acrylic piece, you won’t get as good of performance. It wouldn’t matter where you had the connection pipe, as most of the flow rate from the first pump would be lost in the window area of the reservoir (where the acrylic would normally be bypassing).
Relax, just kidding about the graphics card. It will go in my primary PC while I am installing water-blocks on a pair of HD 6990s. 😉