HIS X850 XT PE IceQ II Dual DVI VIVO 256MB PCIe -
The chip used in the X850 XT PE is the R480 chip. The main difference between this chip and the older R420 chip that you find in the old X800 XT's is so called "process enhancements." These have made it possible for ATI to clock it slightly higher than the X800 XT PE. As you might notice, the Radeon X850 XT PE isn't that much faster on paper than the X800 XT PE.