I have a dual Intel & AMD systems. Just watched a Vegas render a WMV9 HD clip and both processors peak at 97% for a few seconds then return to
about 46%. Are you processing any special effects, extra transitions ?
Is the output format much different than the sorce media ?
this subject was looked into and you are correct - except for mpeg encoding with no effects -- all other rendering using only 1 cpu (or 1/2 of HT -- it renders faster then with HT off)