I got a replacement Gigabyte G1 970 for my first one because the first one buzzed/clicked (I presume this is a form of coil whine or something similar?) and it's not really faring much better. It sounds a bit different/quieter, but generally makes the same noise.
However, I didn't plan on shipping back the first until I got the replacement and for the past hour or so I've been testing out SLI.
It's odd, the buzzing is actually less pronounced in SLI and I'm fairly certain the card in the bottom PCI-E slot (my first 970) is not buzzing or at least not audibly like this. Could my problem be related to my top PCI-E slot? Or SLI maybe just does something differently with power delivery that mitigates the issue? All I can say is coil whine/buzzing of any kind irritates me and I really wish the industry as a collective whole could eradicate or at least identify the root problem.
Different things also cause differing amounts of buzzing regardless of similar GPU usage % and FPS. For example, Unigine Valley and Tomb Raider are relatively quiet, Skyrim produces a very distinctly electrical noise/light buzz, and Crysis 3 makes buzzing quite audible, moreso depending on something as simple as looking in a certain direction and whatnot. Even below 60 FPS (way below), the buzzing's sound, volume, or even frequency seems to correlate not just with framerate, but very specific things being rendered regardless of GPU usage. Overclocking makes the buzzing louder, underclocking has the opposite effect (so much for 970 overclocking, can't because of that infernal noise).
Temperatures are pretty good with SLI 970s. My side fan is currently disabled so the top card will peak in the upper 70s under load right now, but additional airflow should help later on. The fans are quiet too, of course, but that's a moot point with the buzzing.
Performance
SLI 970s (with my 3770K) kick ass. Crysis 3, Tomb Raider, Unigine Valley, Watch Dogs, the Batman games, etc. at 1440p are all doing a constant 60 FPS with settings turned up to 11 (though AA still applied conservatively with Crysis 3 and Watch Dogs).
The Witcher 2 does not like DSR downsampling in SLI for some reason, I'm getting random sustained drops to around 24-40 FPS depending on the direction I look even though neither card nor any of my cores are being stressed to near max. Arkham Origins is also giving me some similar trouble with TXAA in SLI. Unigine Valley drops frames and GPU usage if I alt tab and get back in, crashing later on (no overclock on my GPUs or CPU). Watch Dogs with any AA beyond temporal SMAA has hang ups and dips as if running out of VRAM, and my Afterburner overlay is not able to record memory usage, just stuck on some strange 8-digit or so number.
Overall, when it works, these things give anything a run for their money even at the higher resolution I'm running (This could be my perfect Witcher 3 machine), but Watch Dogs is seemingly running into the 4 GB VRAM wall very easily like this and I'm hoping the other issues are a matter of very immature drivers. Still don't like the buzzing, but I'm tempted to keep both of these now after some time to break them in and think it over.
