My Mum's PC is currently running XP Portable, which is then used to RDP to a decent PC running Windows 7. However, she's unable to play videos (flash, youtube) over RDP so I've had to show her how to jump back to the local desktop and open Iron there when she wants to do so, which is obviously a bit fiddly. Even then the video is a bit jerky but at least the audio is OK.
Her PC is only a HP Vectra Vl400, P3 833Mhz with 512MB RAM and onboard 815 graphics. So I thought if I got her a cheap AGP graphics card, maybe she'd be able to play video over RDP or if not, at least it would play smoothly locally. It might also be worth me building her a Win7 PE/Portable as there's various improvements and patches for RDP available for that.
I was looking at a FX5200 or FX5600 for about £10-15, particularly a model with a heatsink and no fan as I'm trying to keep it nice and quiet. I'm not sure though if RDP uses any specific features on graphics cards that are only available on later generations, so wondered if anyone knows much about this and if I can expect to be able to watch videos over RDP?