ATI Buyer's Guide, Part III: All Graphics Cards!

Sapphire Radeon X1800 XL - Overclocking And Heat

The default clock speeds are given as 500/495 MHz (GPU/memory) in the driver's information center. The same speeds are also suggested as the overclocking presets in the driver's Overdrive tab. In order to overclock the card, the automated clock configuration utility has to be run first, which takes a few minutes; accepting the speeds suggested by the utility automatically selects them. The Sapphire card can be overclocked to a maximum frequency of 574/549 MHz, increasing overall performance by six percent. The memory frequency displayed in the screenshot refers to the physical clockspeed; since this is DDR memory, the clock speeds are doubled in the technical specifications.

The card gets hot, idling at 60°C in 2D mode with the fan spinning at normal speed. Under extended 3D load, the fan speeds up and gets louder while stabilizing the chip's temperature at around 74°C.