You problem is not your fault – Sony Vegas 8.1 is filled with bugs – namely it is super slow in all areas. Stick with 8.0c until they iron out the problems in 8.1. I have two Quad core Pentium 3.0 machines – one 32 bit and one 64 bit, both running Vista Ultimate. The 32 bit machine has 4 gig or Ram and the 64 bit has 8 gig of Ram. The 32 bit machine runs circls around the 64 bit machine with 8.1 on the 64 bit machine. I now am running 8.0c on my 64 bit machine and it is flying. I will wait until they work the bugs out of 8.1. Hope this helps.