The Most Comprehensive AMD Radeon Linux Graphics Comparison

Radeon HD 2600PRO: The Radeon HD 2600PRO uses the RV630 GPU. This graphics card has a 600MHz core clock with 256MB of 1000MHz GDDR2 video memory. When it came to running the Radeon HD 2600PRO with the Catalyst driver, the fglrx driver would produce a segmentation fault.

Radeon HD 2900XT: The highest-end Radeon HD 2000 series graphics processor is the Radeon HD 2900XT with the R600XT core. This power-hungry beast introduced the short-lived 8-pin PCI Express power connector, which was needed in addition to a PCI-E 6-pin power source. Speaking of which, one of the other areas where the open-source Radeon Linux driver lags behind the Catalyst driver is with the power management support. There has been varying forms of power management support by the Radeon driver; it began with "dynclocks" and other xorg.conf options for the xf86-video-ati DDX to adjust the clock frequencies to conserve power and then with KMS this work has been moved into the Radeon DRM driver. As I said back in June, Radeon Linux power management has room for improvement . There's the ability for dynamic power management and to force the GPU into lower power states, but it's not enabled by default and when enabling some of these options they can cause problems -- lockups or other issues if re-clocking takes place during a scan-out. Power management though is another sore spot for Linux and other open-source drivers. The proprietary drivers for both NVIDIA and AMD are better at it then the open-source drivers.

Along the same lines, the open-source Radeon driver also lacks support for overclocking the graphics processor. The Catalyst driver as of 2009 provides support for AMD OverDrive, which allows overclocking the graphics processor and video memory, but there is no support available to enthusiasts on the open-source driver.

This particular Radeon HD 2900XT is made by Sapphire Technology and is clocked at 750MHz for its R600 core and 1650MHz for its 512MB of GDDR3 video memory.