I don't have a Q6600. I own a C0 E8200 that I'm running 24/7 at 3.6GHz. I've pushed it to 3.8 once, seemed stable but when running ORTHOS my temps were getting too high for my taste (that was with my Ultima 90). Now with the HR-01 PLUS, I've taken 8 degrees or so off my IBT temps, so that'll give me enough room to up my voltages again. But my temps are not comparable with yours. Different CPU, different frequency. To give you an idea, IBT will push my core temps and CPUTIN to 52 degrees Celsius.
8 degrees is pretty good. I could live with that if I was to upgrade from my Blue Orb II to the Xigmatek HDT-S1283.
When you just change your CPU multiplier, You're only impacting the CPU so vDIMM shouldn't have to change when you go from 7 to 8. I'm not sure about vPLL, but I operate on the assumption that you shouldn't have to change it either. You can then separate the whole thing into 3 different sections: Mem, CPU and 'The Rest' (essentially the NB). So far we've always kept your memory at rated frequencies so we've never had to worry about memory parameters. When changing the BUS frequency, lowering the CPU ratio prevents you from raising the CPU frequency (you then don't have to worry about CPU voltage). Then you just have to fix 'The Rest'. When that's done, you raise CPU ratio and just have to fix the CPU voltage.
I see. Regardless, my temps were always high and it didn't matter (except for a couple of degrees or so) whether I was at 1.2V or 1.3V for vCPU. But I'll try lowering the vNB, vPLL and vDIMM voltages again, leaving the rest as they are now (1.312V vCPU, 8x ratio and 400FSB).
My temps on a full load without using IBT maxes out at 69-70C on the cores with the settings I use now (3.2GHz @ 1.312V).
In your opinion then, are you confident that I need to replace my cooler? Anything else we can try to "eliminate" that doubt?