Xello, SteveRo, and Nilos, thanks for the input, I tried each of your suggestions individualy and together but no luck, It seems the 21x multi is the the sweet spot for this my cpu/mobo, as lowering the multi doesn't help with the BCLK.

SteveRo- I'm on the UD5, I d-loaded the f4L bios when the f4m was available for the Extreme, I'm assuming it's the same generation

So now my 24/7 o-clock is a choice between 3801 HT on, or 4053 HT off. The only encoding I do is the occasional avi-dvd to burn a DVD, without HT this loads all 4 cores at 60-70%. Outside of that the comp is used for online and gaming, am I giving up much by not using HT ? The only negative effects I see from leaving it on is the higher temps on air cooling.