Radeon HD 4670 512MB vs Radeon HD 7770

Intro

The Radeon HD 4670 512MB comes with a GPU core clock speed of 750 MHz, and the 512 MB of GDDR4/GDDR3/DDR3/DDR2 memory is set to run at 1000 MHz through a 128-bit bus. It also features 320(64x5) Stream Processors, 32 Texture Address Units, and 8 Raster Operation Units.

Compare that to the Radeon HD 7770, which features a GPU core clock speed of 1000 MHz, and 1024 MB of GDDR5 memory running at 1125 MHz through a 128-bit bus. It also features 640 SPUs, 40 Texture Address Units, and 16 Raster Operation Units.

Price Comparison

Specifications

Memory Bandwidth: Bandwidth is the maximum amount of information (measured in MB per second) that can be moved past the external memory interface in a second. It's worked out by multiplying the bus width by its memory speed. If the card has DDR RAM, it must be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The better the bandwidth is, the better the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are processed per second. This figure is calculated by multiplying the total texture units by the core speed of the chip. The higher this number, the better the graphics card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied 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 number is worked out by multiplying the amount of Raster Operations Pipelines by the the core speed of the card. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for outputting the pixels (image) to 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 bandwidth is, the lower the potential to reach the maximum fill rate.