I compressed a 10 minute video today using Squeeze 10. I'm unable to compress using Sorenson 10 standard x264 without crashing on my computer but MainConcept H.264 works fine. I did the compression using the MainConcept H.264 codec and immediately notice a small amount of lip sync problem.
I moved the ProRes file over to my my MacBook Pro where x264 works, compressed it and the lip sync was dead on.
I worked with Sorenson tech support most of last week trying to get the x264 codec to work on my windows Z800, the HP workstation works with the MainConcept H.264 codec, all 24 processors at 99% for a very quick job, but the lip sync, a noticeable few frames off makes it unusable.
My Sorenson settings are never use CUDA, as advised by tech support.