Upgrade Videocard for HTPC

[Shroud]

I have an older Shuttle ST61G4 which is a bit dated and was hoping to breath some new life into it by upgrading the videocard.

The support from Shuttle's webpage is a bit dated as you can see.
http://global.shuttle.com/support_list03.jsp?PI=477

Currently running Windows XP MCE 2005 with P4 3ghz, 1 gig ram, Integrated Video.

I'm only interested in watching movies encoded in x.264/mkv and vc1/wmv and not for playing games on this PC and have considered either purchasing an ATI 2600 Pro or 2600 XT to take advantage of the VC1/H.264 GPU offloading.

Would this be a worthwhile purchase and is there any advantage to GPU offloading with the 2600 XT vs the 2600 pro? I'm guessing the memory difference between the 256 meg and 512 meg isn't worth it, correct?

Forgot to mention the real limitation is the 8x AGP port and the 250w power supply although in a previous review it powered a Radeon 9700 Pro video card so I would think it could handle the 2600 series card.

[Radiator]

You're not going to do any gaming with it ?
And 250W will certainly not be enough , but a stronger PSU is fairly cheap these days .
If you're only going to watch movies , then go for the cheaper , I suppose .

[Shroud]

Hi Radiator,

Thanks for the response.

No gaming as I have a E6600 with 8800GTX as my main gaming machine.

This will be just for watching movies and maybe someday a HD-DVD/Blu-Ray combo drive.

The Shuttle PCs are a bit different then a normal PC, the max power supply that will fit into it is 300 watts, so a 250 really isn't that bad (for a Shuttle)

It only has CPU, Hard Drive and a dvd-rom to power. The 2600 series seem less power hungry then the older 9700 pro video cards.

I guess my questions are for GPU Offloading:
1. Is there any difference between 2600 xt and 2600 pro?
2. Would 512 megs make any difference over 256 megs? (for movies)
3. Is there a 2600 series AGP video card that has HDMI?