First, do you have the latest ATI drivers installed? Also the X1300 is getting a bit long in the tooth now, it's more than two years old which makes it a Methuselah for 3D graphics.

Second, in my opinion, buy an Nvidia card. I have a machine similar to yours, but with an Nvidia 8800GTX. Intel Core 2 Quad, Intel chipset mother board, XP Pro 64 bit. The graphics preview works mostly, there's always a surprise or two but nothing like what it seems you're having.

(I forget where, but there was a forum where someone had a poll asking which video cards worked best with 3D software. I don't think a single respondent supported ATI. Kinda sad for me, since ATI used to be Canadian and I am Canadian too.)

Disclaimer: My opinions, based on my experience. Your mileage may vary.

(It's really annoying when I use Linux at home, I'm paid to work on Linux at work, but the only 3D graphics card I recommend is the only one that does not have free drivers for Linux.)