8800GTX XXX Edition SLI Problem

[fsofos]

Last February i purchased 2 XFX 8800 GTX XXX Edition cards which had also consecutive Serial Numbers which is one in a million spot. At the time i had utilize one of them because i did not had in place an SLi ready motherboard. Recently i installed an EVGA nForce 780i motherboard which is updated to the latest Bios (Regarding the Infamous Graphics Corruption lockups), But i waam not so lucky.The moment i place the second 8800GTX and enable SLi i have numerous problems especially in games. Graphic artifacs, lockups, bsod`s to name a few. When i disable sli an take out the second graphics my problems are gone. I have a very good ventilated case (Coolermaster Stacker 830 NVIDIA Edition with 8x120mm fans), and a strong enough SLi Ready power supply (PC P&C 1000W-SR) so i rule out the problem of power and cooling. I believe that the second graphics (Serial ending at 310) has a problem. I have to state that i have 2 spare XFX 8800GT XT edition cards which perform ok. Please advice for RMA procedure....

[Miker]

Why not put Card 2 in slot1 and see if it works?

SLI is hard to set up, you did install the drivers? Also, does the 2nd card show in device manager?

[werty316]

If he has 2x8800GT cards that work fine in SLI then theres a good chance one of his 8800GTX cards is borked.

SLI runs in PCIx slots 1 & 3 on the 780i and SLI is far from being hard to set up.

Does each 8800GTX run fine on its own?

My advice is to try switching the 8800GTX cards around to see if you still get this problem when running them in SLI.

[fsofos]

Thanks fro your replies.

I did manage to change the cards around and things got even worse, and yes i set up my sli using slots 1 and 3 which are the PCi-E 2.0 compatibles. At the moment i am using the 8800GT's with no apparent problems so far. I am monitoring them to see their temps and behavior. I am not overclocking and i use the correct timings for memory.
I am using extreme versions of XFX cards since the days of 7800 GT's and i never had a problem like that. But i have to admit this is my 1st SLI with XXX edition cards. I believe that the second card has the problem.
Please advice....

[xfxsupport]

I would try the second card by itself to see if you have issues. If so start a support ticket at www.xfxforce.com. At this point we need to verify if the motherboard is having issues with SLI or one of the cards is not working correctly.

[fsofos]

Before i test the second card by itself i am installing the latest WHQL Driver 174.16 and i using Rivatuner to downclock the card at default settings (575/900) instead of 630/1000). I will post back with results.....
Thanks again for your support.
I already have a support ticket for this subject. I will PM you the number....

[Miker]

SLI with a OCed card can be hard too. After you make sure both cards run in slot too I would underclock them to the stock speeds of the card and see if it works.

[fsofos]

I installed the latest 175.16 drivers for Vista 32-bit.
Installed Rivatuner 2.09.
Downclock the cards to 575/900(Core/memory) and set the Fan speed at 100%.
Played Crysis for 1 hour at 1920*1200(Very-High settings no AA) with no problem.
I have to state that my problem is maingly the BSODs with "Nvlddmkm.sys" on Vista 32bit (http://www.bjorn3d.com/forum/showthread.php?t=23381) or 64-bit.
But i want support to aswer the following question:
I purchased 2 cards that are Factory overclocked to 630/1000(Core/Memory) to run SLI with my 24'' Monitor at native resolution with acceptable frame rates. What is the point to downclock the cards if they cannot perform as advertised? What can i do for to remedy that situation?
Please advice.

PS: I will keep testing today with LOST Planet DX10 to see what happens.