I have a old theater pc powered by a x2 4800 processor, a ton of ram, and a new 6450 video card. I'm using media center XP using this guide http://www.avsforum.com/avs-vb/showthread.php?t=1357375 to set up MPC.
When I have hardware processing enabled, my cpu runs at about 30-60%. When it is not enabled, the cpu runs at 90%.
I'm getting a ton of stuttering either way. I never had this in Theater Tek, or My Theater.
Time for a rebuild, or reformat?
Will my hardware suffice?
I'm also using a RS45 with a DVDO edge
I would think your hardware could handle most common HTPC needs, its not much different than mine, but I'm running Win 7 64 bit and XBMC with no other post processing. I think Win 7 performs better than XP on older systems, so you might consider trying an OS upgrade before rebuilding.
If, however, you are like me and just want an excuse to upgrade, then my answer could be changed.....
You might consider just running a trial version (not entering a key). I think you can get by with that for a few months, certainly long enough for you to see if it is meeting your needs on the old machine. (Google: how to re-arm Windows 7)
This is a decent deal on the family pack upgrade. It is not OEM so should be movable to new systems plus you can upgrade 2 additional systems. (Just in case you have other systems on now or in the future)