Which IGP solution is best for HD playback?

[buddyglass]

Apologies in advance if these questions are newbie-ish.

I'm looking at building a HTPC based around the Silverstone LC19 slim case and the Hauppauge HVR-1600 tuner. The primary use will be recording ATSC over-the-air broadcasts, but I also want to use it as a DVD player.

Since the LC19 case only has one expansion slot, I'm going to need to use and IGP solution for video since the tuner will take up the expansion slot. The IGP contenders seemd to be the Intel GMA X4500HD, the Nvidia Geforce 8200, and the ATI Radeon 3200 HD.

Which one is my best bet for getting HW accelerated HD (MPEG-2 and H.264) playback using SageTV?

Also, will I need Vista, or can I make do with XP?

[stanger89]

I know the 3200 will work (in XP) since I've got one, but I'd lean toward the other two as they support multichannel PCM audio.

[buddyglass]

Generally speaking I prefer to use Intel chipsets and CPUs, but in this case the selection of power efficient CPUs seems to be better on the AMD side. It comes down to:

AMD Athlon X2 4850e (2.5ghz, Dual-Core, 45W)
Intel Celeron 440 (2.0ghz, Single-Core, 35W)
Intel Core 2 Duo E8400 (3.0ghz, Dual-Core, 65W)

If the single-core Celeron has enough oomph to handle simultaneous HD capture and playback (e.g. watching previously recorded content while capturing new content), then that would be my preference since it draws less power and should be more easily (i.e. quietly) cooled. But...somehow I doubt it's up to the task.