Buggy, coz that's not how it should behave. I'll try turning off CnQ & Turbo core, although I like the idea of turbo boost. Or core. Whatever. In the meantime, I flashed the BIOS of my mobo again, and that of both 570s, updated drivers for my motherboard, etc. No DICE. EDIT: it seems a lot of people on AMD rigs have the same problem. Someone has posted the following interesting theory about the problem, on nVidia forums: What do you think?