Radeon HD 3870 512MB vs Radeon HD 7770

Intro

The Radeon HD 3870 512MB features a core clock frequency of 775 MHz and a GDDR3 memory frequency of 900 MHz. It also makes use of a 256-bit memory bus, and makes use of a 55 nm design. It is made up of 320(64x5) SPUs, 16 Texture Address Units, and 16 Raster Operation Units.

Compare those specifications to the Radeon HD 7770, which has core speeds of 1000 MHz on the GPU, and 1125 MHz on the 1024 MB of GDDR5 memory. It features 640 SPUs along with 40 TAUs and 16 ROPs.

Price Comparison

Specifications

Memory Bandwidth: Bandwidth is the maximum amount of information (measured in MB per second) that can be moved across the external memory interface within a second. The number is worked out by multiplying the card's bus width by the speed of its memory. In the case of DDR type RAM, the result should be multiplied by 2 once again. If DDR5, multiply by 4 instead. The better the 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 are processed in one second. This is worked out by multiplying the total amount of texture units of the card by the core speed of the chip. The better this number, the better the graphics card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels in one second.

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