Overclock YOUR ATI video card. Detail inside!!
There's a nifty program for all you unaware to over clock almost any ATI graphics card. It's called ACTccelerator II, and it can be found over at www.macupdate.com. I was even able to overclock the graphics chip in my iMac G3 Classic. Not much, but still noticable. Clock: 130Mhz to 150Mhz, Memory: 130Mhz to 150Mhz. Check it out.