Radeon X1800 GTO to X1800 XL Mod?
The post is not in english, but the pictures at HKEPC tell the whole story. It seems that some (perhaps all) Radeon X1800 GTO cards can be easily modified to unlock the additional 4 pipelines lurking within the R520 GPU. HKEPC used an HIS card, and simply flashed the BIOS with a modified version that unlocked the additional pipelines. This is basically the same mod procedure used to unlock the disabled pipes on the Radeon X800 GTO as well.