Yep, you'll find a higher-spec graphics card will help. The SiS 530 isn't really designed for games. I'm upgrading to a GeForce2 GTS 32MB next week. If you don't want to splash out that much, then consider the GeForce2 MX series of cards.
One caveat - if the machine has only PCI slots, then you'll need to try and locate a new PCI graphics card. Two suggestions here: a Voodoo 3 2000 or an NVidia TNT2-based card. You really don't have much choice when it comes to fast PCI graphics cards.
However, if you've got an AGP socket, get the fastest card you can afford. Also, upgrade to DirectX 8.0.
[This message has been edited by MegaTop744 (edited 22 March 2001).]