A while back, I downloaded version 1.0.0rc1 and my computer ran the HD files perfectly. Then all of the sudden, it stopped working well, making the video choppy and had a lot more computer usage then normal. Upgrading to rc2 hasn't helped at all. Closing out other programs doesn't help at all and i had the video output set to Windows GUI. Is there any solution to this problem? 1.0.0 was the one that worked best out of all the versions. Here's my specs.
Windows Vista
Processor: AMD Turion(tm) X2 Dual-Core Mobile RM-70 (2 CPUs), ~2.0GHz
3 gig RAM
Video Card: ATI Technologies Inc. ATI Radeon 3100 Graphics (updated to the latest driver)