Radeon HD 4850 2GB vs Radeon HD 6790

Intro

The Radeon HD 4850 2GB makes use of a 55 nm design. AMD has set the core frequency at 625 MHz. The GDDR4 memory works at a frequency of 993 MHz on this particular card. It features 800(160x5) SPUs as well as 40 Texture Address Units and 16 Rasterization Operator Units.

Compare those specs to the Radeon HD 6790, which features a core clock speed of 840 MHz and a GDDR5 memory speed of 1050 MHz. It also uses a 256-bit memory bus, and uses a 40 nm design. It is comprised of 800 SPUs, 40 Texture Address Units, and 16 Raster Operation Units.

Price Comparison

Specifications

Memory Bandwidth: Bandwidth is the maximum amount of data (counted in MB per second) that can be transported over the external memory interface in one second. It's worked out by multiplying the interface width by the speed of its memory. If the card has DDR type memory, it must be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The higher the memory bandwidth, the better the card will be in general. It especially helps with AA, High Dynamic Range and higher screen resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are applied per second. This is worked out by multiplying the total number of texture units of the card by the core speed of the chip. The higher the texel rate, the better the graphics card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in a second.

Pixel Rate: Pixel rate is the most pixels that the graphics card could possibly write to the local memory in one second - measured in millions of pixels per second. The figure is worked out by multiplying the amount of Render Output Units by the clock speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel rate also depends on lots of other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the ability to reach the maximum fill rate.