the memory i have is designed specifically to go at 275Mhz and to have 2.5-4-4-8 timings at that speed and 2.75 v, HTF i have always been able to get it 10% over at 220*5 or 275*4, also have a thermalright xp-120, which is very good at keeping it cool, and i have a swiftech copper chipset cooler, so maybe that is why i can do it am not sure, however i recently experienced hard drive corruption and reinstalled putting my system back to default speeds and tightening my memory to 2-2-2-5 at 200Mhz, i don't know what caused the hard drive corrruption, maybe it is a bios issue or maybe you are on the right track with the HTF not being able to go above 1000Mhz, or could be any number of reasons, however i nenver got aany corruption at 220*5 so am pretty sure it is more likely to be the weird problems with the bios, unless anybody could give some more insight, think i will wait for new bios to come out then do some more tests, if nothing comes of new bios, maybe e-mail ASUS and see if they have any ideas?