I've tried installing many 3-D games, like Cube, openArena, Nexuiz, TuxRacer, etc. etc., but the only 3-D game that has worked so far is Armagetron. Google Earth just plain crashes X when I try to start it, and it's been this way ever since I got this computer.

I'm guessing it has something to do with my graphics drivers, or my card. I've been using the one that's built in to my motherboard, a SiS card, and the only 3-D acceleration stuff I've found is for nVidia or ATI.

OpenGL is extremely slow on my computer. I'm guessing that's because of the graphics card. Correct me if I'm wrong.

So should I go out and buy a better graphics card, or is there a less expensive way to get my card to work faster? Maybe somewhere far away, there something for SiS?

Thanks in advance.

Longer answer:

Typically built-in/integrated graphics hardware is weaker than external cards, and in Linux world if you don't have either ATI or nVidia card, you're probably out of luck with hardware 3d accelaration. There are other manufacturer cards that might work, but I'd say most of the users who want to run hardware accelarated 3d things on Linux and stay sane just own nVidia/ATI card - they aren't 100% non-problematic either, but with the mainstream distributions their driver installs are nowadays (most of the time) painless and do work. nVidia chipset cards are said to work better on Linux, but ATI chipset cards work well too, provided that the manufacturer has a driver for the specific model for Linux (see their site).

Short answer: buy an external 3d card.

Reasons: it's not expensive. You can get a little older 3d cards for small amount of money, practically pocket money. If you are hoping to get your integrated SiS graphics hardware run your games, you probably aren't going to buy the newest king of the graphics hardware anyway (close to $1000 in price), and that means you're very probably satisfied with the cards that are actually affordable. I don't think you can even get a sucky 3d card today, at least if you stick to nVidia or ATI cards and check that their manufacturer's website lists them to have Linux driver support.

If you're a hardcore gamer, you own a gaming console or at least Windows XP and Vista to be able to play most of the games available, and you do have the money and will to buy the graphics hardware that costs nearly as much as good SLR optics today. If you're not, you should leave your weekly candy to the store for a month and put the money into your 3d card instead.

EDIT: to test, run
for a moment from a terminal and see the output. If you get low FPS, it's probably because either your hardware can't do it or you don't have drivers that could actually get something out of your hardware (for drivers: manufacturer's website either says you can get Linux drivers and assists in that or then you're out of luck, unless you're a mad hacker-programmer-magician). Also run
and see what it says (in the beginning) about direct rendering. "yes" means you should be able to run 3d stuff smoothly, "no" means you can't. OpenGL or not, if your hardware and drivers can't do it, nothing can.