When using fglrx drivers,
should say, among other things, that DRI (Direct Rendering Infrastructure) is
enabled and the driver should
not be Mesa but your ATI driver instead. This is when the driver is working all right, and you should get high fps. If the driver is Mesa or especially if DRI is disabled, you'll get low fps. VESA driver is a low-resolution low-performance driver, and if your fglrx gives same level fps than VESA driver, you have something wrong.