Intel Pentium 4 vs. Pentium D 940

I run Adobe Premier 6.5 on these computers. I just acquired the 3.2ghz Pentium D 940 hoping it would be faster for what I do, but my older 3.4 ghz Pentium 4 seems a lot faster converting timeline projects to AVI. Projects that used to run just hours now runs well over a day, and then some. Is there any tweak that can be done or I’m just stuck with it?