HELP!!! virtualdub takes 4.5 hours for each pass

[boibku]

I recently re-formated my computer. After that, I installed the newest virtualdub for p4. I used the same version before I formated my computer and it took about 2 hours to process each pass. But now it takes about 4.5 hours for each pass. It kills me to wait this long. Please help me if you know how to fix this, maybe I missed some settings?
thanks.