AMD Radeon HD 4770 On Linux

Overclocking the Sapphire Radeon HD 4770 via OverDrive on Linux was not ideal. The RV740 core has a default frequency of 750MHz and its 512MB of GDDR5 memory is running at 800MHz, while the configurable peaks are 500 to 830MHz and 800 to 850MHz, respectively. With ease, we had no problems pushing the 40nm ATI GPU from 750MHz to 830MHz. When the GPU core was running at this maximum OverDrive frequency we had not run into any issues whether it is stability problems or artifacts. Where we ran into problems was with adjusting the GDDR5 frequencies. When touching the GDDR5 frequencies even by just a few Megahertz, when initializing an OpenGL program the system would lock up. Even when running the GPU at its default speed, the GDDR5 memory could not be adjusted without running into problems. With that said, for our overclocked Radeon HD 4770 results we ran the graphics card at 830/800MHz compared to 750/800MHz.

The graphics cards we tested in the same setup with the same software and drivers to compare the Radeon HD 4770 performance was a Radeon HD 4670 512MB clocked at 750/1000MHz, a Radeon HD 4830 512MB clocked at 575/900MHz, a Radeon HD 4850 512MB clocked at 625/993MHz, and a Radeon HD 4870 512MB clocked at 750/900MHz. As the Radeon HD 4770 was designed to go head-to-head against the NVIDIA GeForce 9800GT, we also threw one of those graphics cards into the mix with 512MB of video memory and was clocked at 660/950MHz. For the 9800GT testing we used the NVIDIA 185.18.08 display driver.

All Linux testing was managed through the Phoronix Test Suite using the latest 2.0 Sandtorg code-base. The tests we ran included Nexuiz, World of Padman, Enemy Territory: Quake Wars Demo, Unigine Sanctuary, Unigine Tropics, Lightsmark, GtkPerf, and QGears2.