In terms of overall gaming performance, the graphical capabilities of the AMD Radeon HD 5870 1024MB are noticeably better than the AMD Radeon HD 6850 Sapphire 1GB Edition.

The HD 5870 has a 75 MHz higher core clock speed and 32 more Texture Mapping Units than the HD 6850. This results in the HD 5870 providing 30.8 GTexel/s better texturing performance. This still holds weight but shader performance is generally more relevant, particularly since both of these GPUs support at least DirectX 10.

The HD 5870 has a 75 MHz higher core clock speed than the HD 6850 and the same number of Render Output Units. This results in the HD 5870 providing 2.4 GPixel/s better pixeling performance. However, both GPUs support DirectX 9 or above, and pixeling performance is only really relevant when comparing older cards.

The HD 6850 was released over a year more recently than the HD 5870, and so the HD 6850 is likely to have better driver support, meaning it will be more optimized for running the latest games when compared to the HD 5870.

The Radeon HD 6850 Sapphire 1GB Edition and the Radeon HD 5870 1024MB have the same amount of video memory, but are likely to provide slightly different experiences when displaying game textures at high resolutions.

The HD 5870 has 25.6 GB/sec greater memory bandwidth than the HD 6850, which means that the memory performance of the HD 5870 is slightly better than the HD 6850.

The Radeon HD 6850 Sapphire 1GB Edition has 960 Shader Processing Units and the Radeon HD 5870 1024MB has 1600. However, the actual shader performance of the HD 6850 is 372 and the actual shader performance of the HD 5870 is 680. The HD 5870 having 308 better shader performance and an altogether better performance when taking into account other relevant data means that the HD 5870 delivers a significantly smoother and more efficient experience when processing graphical data than the HD 6850.

The Radeon HD 5870 1024MB requires 188 Watts to run but there is no entry for the HD 6850. We would recommend a PSU with at least 500 Watts for the HD 6850 and a PSU with at least 500 Watts for the HD 5870. The two GPUs have been recommended a PSU with the same amount of wattage. As such, there is no need to worry about which will more significantly affect your yearly electricity bills.