1080i Playback

I have access to what is supposed to be a "high-end" system. It is a Dell Precision 690, 2 hard drives in RAID0 configuration, 1.60 GHz Xeon, 1 GB RAM, with an ATI FireGL V7200 video card.

Recently, I have begun experimenting with 1080i HD video. The problem I am having relates to dropped frames when playing from a file stored on the hard drive. According to a test utility this system is only capable of displaying 24 frames/second. I need to speed-up HD playback on this system if possible.

Can anyone recommend what would provide the most bang-for-the-buck?

- a faster processor and/or a second processor
- faster hard drives and/or a faster RAID0 controller (the system has SATA-150 drives at present)
- another codec
- a better graphics adapter
- anything else that I haven't thought of

Thanks for any advice,
Tom