Yeah, I was a bit surprised with the artifacting way back when I got the 9550; before that I'd had a GeForce3 ti200, and then a GeForce4 ti4200, and then a Radeon 9600 (the 9550 is essentially an underclocked 9600 with no fan). It was odd when moving from the 9600 to 9550 that problems cropped up.
I have half a dozen computers; the oldest (built in 2001) still runs 98SE and I love it. Look up KernelEx and RP9 if you want to know how I run modern software on 9x. All the other (much newer) machines run XP (varying versions depending on which license was bought for which machine). The 9x machine is still my favorite, even when up against a multicore, 4GB DDR2, nVidia GTS 250 beast. I have a 1.3 GHz Athlon, a whopping 512MB of non-DDR RAM (underclocked to 100 MHz), Radeon 9550, and ~600GB of hard drive space (120GB IDE, 500GB SATA via PCI SATA card) in this bad boy. It's on 24/7 and has uptimes measured in weeks.
The GTS 250, to my surprise, renders JK just fine aside from horrible texture color banding.