My FPS within WoW regions varies from 20 - 60+ depending on region and the amount of players there. My main concern is end game instances, which I generally achieve in 40 man raids between 5 - 25 fps. Most times it the lower end. I have turned every setting down and made tweaks to my Vid card without much success. My lower FPS does occur when I have decent Lat but obviuosly goes down the toilet with bad Lat. Below is my current hardware. If there is anything I can do to help me out that would be great.

Processor:
2.80 gigahertz Intel Pentium 4
16 kilobyte primary memory cache
1024 kilobyte secondary memory cache

MB:
Gigabyte Technology Co., Ltd. 8IPE1000-G/L x.x
Bus Clock: 200 megahertz
FB: 800 megahertz

Memory:
Corsair - TWINX1024-3200C2PT x 2 = 2048MB
Freq: 400 mhz

Vid Card -
Graphics Chipset RADEON X1600 Series
Current Bus Setting AGP 8X
Memory Size 512 MB
Memory Type DDR2
CATALYST® Version 06.6

Windows: Windows XP Home

* The Radeon card is a upgrade from a GeForce FX 5900 256Mb.