Overclock.net › Forums › Graphics Cards › NVIDIA › <HELP PLEASE!> Defect in GTX 780 causing SLI failure? (Black screen / Sound loop)
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<HELP PLEASE!> Defect in GTX 780 causing SLI failure? (Black screen / Sound loop)

post #1 of 3
Thread Starter 
This is my "first time" to post on the forum!... excited, nervous, and wondering if it will hurt, haha. Please be easy on my virgin attempt. Enough innuendo and on to the topic at hand. I apologize in advance if I don't follow the forum rules please let me know and I will make the appropriate changes.

Now lets get to it... After building my dream machine (see my profile for pics), I've been running into a glitch: Any graphically intensive program will Black Screen (no input detected by monitors) and continues to run a sound loop. The system goes non-responsive and I have to force restart on the front I/O after this occurs. It appears to happen at random, with and without OC, and is indiscriminate as to what program it does it with. I do run 2x GTX 780 SC on Nvidia Surround (3x Acer 24") and the system is WC. [See below for system specs]

After some intensive trouble shooting I know the following:
- No Mini dumps, no Event Report
- Still occurs with the previous 3 GeForce drivers
- All other hardware is properly working (CPU, PSU, Mobo, etc.)
- No Win 7 file or SSD corruption
- Each GPU will run independently without problem (No Black Screen) and OC by itself no problem
- Each GPU will OC independently significantly higher than can be obtained in SLI
- Higher OC in SLI increases the frequency of the Black Screen
- Switching GPUs to a different PCI-e slot has no effect
- Re-applying TIM to GPU_1 did not decrease the temperature difference between the cards

So logically, if there is no hardware issues or program errors and the GPUs running independently do not create the Black Screen, the problem must lie in the interaction of the 2 GPUs. So lets compare...

2x GTX 780 SC in SLI - (03G-P4-2783-KR)
[Both OC @ +78 MHz core clock / +150 MHz mem clock / +.38 mV / 106% power target] [OC data mirrors differences between cards @ stock]

- ASIC of GPU_1..............65.5%
- ASIC of GPU_2..............70.8%

GPUs idling
- MHz of GPU_1................941
- mV of GPU_1..................1.012
- temp (C) of GPU_1........32 C

- MHz of GPU_2.................941
- mV of GPU_2...................1.000
- temp (C) of GPU_2..........28 C

GPUs under load (both at 92% workload)
- MHz of GPU_1................1137
- mV of GPU_1..................1.187
- temp (C) of GPU_1.........50 C

- MHz of GPU_2.................1150
- mV of GPU_2...................1.200
- temp (C) of GPU_2.........43 C

So my main thought is... a small defect in one of the cards, related to SLI, resulting in the black screen? Thoughts on this? Also, the 7 C difference between cards under load is concerning but not necessarily indicative of an issue. ASIC also catches my attention, in that a 5% difference could possibly be effecting the compatibility of the cards? That being said I would really appreciate any help from the vast knowledge you guys possess.

- i7 3770k (@ 4.5 mhz)
- Asus P8Z77-M Pro
- Corsair Vengeance 1600 (16GB)
- 2x EVGA GTX 780 sc (in SLI)
- Samsung 840 Pro (512GB)
- Corsair HX1050 PSU
- 3x Acer G246HLAbd (Nvidia Surround)

- XSPC Raystorm LGA1150
- 2x XSPC Razor GTX 780/780ti/Titan w/ back plate
- Swiftech MCP35x w/ XSPC top & Koolance heatsink
- Alphacool NexXxoS ST30 - 240mm rad
- Alphacool NexXxoS UT45 - 280mm rad
post #2 of 3
Thread Starter 
post #3 of 3
Hmm... Quite a build you have there! Ok I would have said the fault lies in the PSU but then I saw it was 1050w... But you said increasing the OC was increasing the frequency of the black screen.. You mean a noise? Maybe there's a problem with your PSU delivering enough power to the cards or being under powered for all that.. Dont quote me on it though. Since your PSU is modular, have you tried changing where the modular cables plug in? And is it possible to find a different PSU to test? I'm pretty sure your local computer store can help you uncover this mystery:) PM me if anything else is needed!
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