Problems with GA-X79S-UP5 board - please help!

[massman]

It's not just happening on C2, my C0 exhibits the same issue.

From what I'm hearing, they are saying it's a CPU-related issue not a mainboard one. Did you swap out for another mainboard brand already? If yes - same issues?

//edit: couldn't wait for the reply, tested P9X79 with the same C0 chip and so far no throttling

//edit2: went back to the X79S-UP5 to test behavior with gear ratio at 1.25X. Now I don't have throttling at 4.25GHz anymore (34x multiplier), but around 4.75G (38x) it would throttle back to 37x once every minute or so (under high load). It seems like the throttling occurs more often and in larger steps the higher the multiplier you're using (and not related to temperature, voltage or frequency). I'll go back to the P9X79 to double check if no throttling takes place.

//edit3: back to P9X79 running 4.5G (45x) OCCT AVX-enabled and no throttling; on the same bench with the X79S-UP5 at 4.3G (43x) it'll drop back to 42x and 41x once every 15-20sec. As said, at 4.75G (38x) it only throttles back one step (37x) every 60sec or so. As far as I can tell, the engineers are working on it (or at least aware), but so far didn't see a bios that fixes the issue. I'll keep you updated.