Radeon HD 4890 2GB vs Radeon HD 6870

Intro

The Radeon HD 4890 2GB has a GPU core clock speed of 1000 MHz, and the 2048 MB of GDDR5 RAM is set to run at 975 MHz through a 256-bit bus. It also is comprised of 800(160x5) SPUs, 40 Texture Address Units, and 16 ROPs.

Compare all of that to the Radeon HD 6870, which has clock speeds of 900 MHz on the GPU, and 1050 MHz on the 1024 MB of GDDR5 RAM. It features 1120 SPUs along with 56 TAUs and 32 Rasterization Operator Units.

Price Comparison

Specifications

Memory Bandwidth: Bandwidth is the max amount of information (measured in MB per second) that can be transported past the external memory interface within a second. The number is calculated by multiplying the card's bus width by its memory speed. In the case of DDR type memory, the result should be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The higher the card's memory bandwidth, the better the card will be in general. It especially helps with AA, HDR and higher screen resolutions.

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

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics chip could possibly record to the local memory in one second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the number of ROPs by the clock speed of the card. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel fill rate is also dependant on many other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to reach the max fill rate.