Whats the best way to determine which 2 of 4 GPUs are most compatible for OC in SLI?

[Neon01]

Any tips here? I have currently 4 GTX 980s and will be keeping 2 of them for SLI, and I was hoping there might be some characteristic that I could check to see which two might be best together for SLI and OCing. That is, without testing each pairing in a large battery of benchmark tests...

I ask this because I've seen instability issues with two of my cards that seem to be related to a voltage disparity while operating. In some programs I can OC them to well past 1500MHz, while in others they have issues at 1450MHz. The voltages are routinely at least 50-60mV apart under load.

I've read that cards with similar ASIC usually have similar voltage under load, and this may translate to better OC stability and higher OCs. Is this true? If so, maybe I could just pick the two that have the closest ASIC? If not, would observing voltage under load and picking the two of those that are the closest be the best way to do this? Should I compare them while running only a single GPU in the system?

Any thoughts? I'm hoping to avoid messing with hours of benchmarking 4 different SLI pairings. If this can't be done relatively easily I'll probably just pick two and call it a day.

 

[sonsonate]

The voltage difference is pretty much a known issue (?). Google and you'll get a ton of results.

As for picking the "right" card, are you really going to miss a couple tens of megahertz and possibly a single frame? The performance increase from 1 card to 2 is pretty large to be fussing over something that small.