I am looking to upgrade the video card in my PC which doubles as our HTPC linked to our TV via S-Video.

Currently I am running a ATI Radeon 9600/X1050 series which is a few years old now but is generally suitable for SD TV and download DIVX etc although it seems to struggle a bit with HDTV and 720p MKV files. HD stuff tends to play for a bit but CPU usage goes through the roof and then it stutters too much to be watchable.

The PC is an old AMD Athlon XP 2600 with 2GB ram and 8x AGP slot on motherboard which I know needs to be replaced but I am hoping to find a card that will take enough load off the CPU and allow me to watch HDTV and downloaded 720p content. Gaming not needed.

I have been doing some research through other threads and it seems that my options are;

Nvidia Geforce 7600GS
ATI HD3650 Radeon

Can anyone confirm if either of these options would be suitable to keep the old beast running for another 12 months until I can upgrade the whole system or are there any other cards that would do the job for me.