Athlon Tbird/XP plus a 4670 ?

[hertswenip]

I have a few Tbird (900- 1400) and XP (1433-1833mhz) cpu/agp mobo's laying around Id like to put to good use. I have conisdered getting something like an AGP radeon 4650 so I could build an HTPC capable of HD playback.

Now I have read dozens of threads/forums re: this topic, and everyone is saying 1080p playback is not possible without a multicore processor, but is this just theory, or has anyone actually tried using an hdmi card with a single core processor?

It is my understanding that the current HDMI blue ray cards offload nearl all of the video-decoding from the CPU to the GPU, so my question is- would smooth 1080p playback be possible with an older single core CPU like a tbird or xp athlon? If not, do you know anyone who tried such a combination with a capable card?

 

[deadjon]

http://www.guru3d.com/article/accelerate-x264-1080p-movies-over-the-gpu-guide/

This ^

Basically its a guide to encode movies to run entirely off the GPU.

The above guide shows how you can get a 1.6ghz Single Core Atom to run at 25% CPU Usage when running 1080p vids.

[EDIT] The Tbirds will probably struggle. Anything above an Athlon XP 1800 should cope with it assuming you get the right setup and software.