ATI Radeon X850 XT PE

With 16 pixel pipelines and six vertex shader units, the X850 XT PE is an exact match in specifications to its predecessor, the X800 XT PE. All that's different is the slightly raised clock speed: 540/590 MHz versus 520/560 MHz. Externally, the differences are much clearer.

While ATI has long criticized the dual-slot cooling solutions that rival NVIDIA has used in its top models for some time, it has fitted its X850 XT PE with just this type of cooler. Without it, the huge level of heat that builds up in the 130-nm Low-K R480 chips cannot be sufficiently ventilated at these clock speeds. Heat from the graphics processor and memory module is transferred to copper cooling fins. A large fan directs the air through a transparent plastic housing and forces it out of the case through the slot panel.

The fan makes quite a racket when the computer is booted, but switches to a whisper-quiet mode after a few seconds. Even during 3D operation, it's scarcely noticeable.

As a further special feature for the reference card, ATI gave it two DVI-I display outputs.