Strange performance on new mobo. Help!

I just upgraded my system from an Athlon 900/Abit K-T7 board to an Abit IS7 board with 2.4 Pentium 800 front side bus. The system is stable, but has stange gaming performance. Specs are WD 120 7200 HD, 2 512 meg Kingston ram running in dual config, Audigy sound card, and MSI Geforce 3 TI200. Running dual boot Win 98SE and XP. Everything is a fresh install on the hard drive (brand new drive). I'm getting better frame rates in benchmarks and in games, but a lot of games are smooth, but jerky. That is if I stand still, everything around me moves silky smooth, but as I turn/ move forward etc, the movement is smooth, stutter, smooth, stutter. I've tried various drivers for the video card, I'm running directx 9.0. It does the same thing in both 98 and XP. On the old system, even though the framerates were lower, it wasn't as jerky, I could actually do better in Battlefield 1942 before the upgrade, now I'm not doing as well because I can't figure this stuttery problem out. In BF 1942, I've even set every possible setting as low as possible, and it still is stuttery, even though the framerate get even higher. Can the processor/mobo actually be too fast for this geforce card and it can't keep up? Is there some bios settings I should try? Could something else be causing this? Any advice would be appreciated. Thanks.