ATI Graphics Card Buyer's Guide 2006, Part II

Sapphire Radeon X1800 XT OC - Overclocking And Heat

The default clock speeds are given as 594/693 MHz (GPU/memory) in the driver's information center. The suggested overclocking presets in the driver's Overdrive tab are 695/792 MHz, making them identical to those of HIS's iTurbo version of the card (tested in Part 1 of this guide). In order to overclock the card, the automated clock configuration utility has to be run first, which takes a few minutes. We were able to complete this process once, albeit with a meager clock speed increase of 1 to 3 MHz. When we attempted to rerun the configuration process, we ran into the same problem as with the HIS card: we had to manually abort the utility, as it was unable to return a result even after 30 minutes. This confirms that Sapphire's clock speeds are already extremely close to the limits of the chips. The memory frequency displayed in the screenshot refers to the physical clock speed; since this is DDR memory, the clock speeds are doubled in the technical specifications.

The chip's temperature is high. In 2D mode, it runs at 62°C, and when a heavy 3D load is applied, its temperature rises to 91°C. The powerful fan is up to this thermal challenge, although it can get quite loud.