Vegas Pro 10 has greatly improved playback of H264 files on the timeline to the point that my elderly system (C2D E6300) can actually cut footage in real time (don't ask me about adding fx).

However, playback in the trimmer is extremely slow. I know some people don't even touch Vegas' trimmer, so this isn't a problem, but I like the trimmer. I like reviewing and setting markers/regions on my clips before I start editing. However, with my current system (see above), the trimmer is unusable.

My question to those of you with more current systems: What type of performance do you get?

I'm mostly interested in the trimmer performance. Playback, jog/shuttle, forward, reverse, etc. I'm about to build a new i5 system (2500k-based) and I'm wondering whether it'll be worth it. Vegas 10 got a performance boost with H264 because of some optimized coding, but it doesn't look like those optimizations transfer to the trimmer as well.

Do you get good performance (smooth/responsive playback) in the trimmer on your system? What are your specs?

Even though I just upgraded to Vegas 10, I'm considering moving over to Premier CS5 because I can basically guarantee playback performance with a $80 video card. I still love Vegas, so please tell me I don't have to do this :(