Radeon HD 4670 512MB vs Radeon HD 7850

Intro

The Radeon HD 4670 512MB uses a 55 nm design. AMD has set the core speed at 750 MHz. The GDDR4/GDDR3/DDR3/DDR2 memory runs at a frequency of 1000 MHz on this particular card. It features 320(64x5) SPUs as well as 32 Texture Address Units and 8 Rasterization Operator Units.

Compare that to the Radeon HD 7850, which uses a 28 nm design. AMD has set the core frequency at 860 MHz. The GDDR5 RAM runs at a speed of 1200 MHz on this card. It features 1024 SPUs as well as 64 TAUs and 32 ROPs.

Price Comparison

Specifications

Memory Bandwidth: Memory bandwidth is the max amount of data (measured in MB per second) that can be moved across the external memory interface in one second. It is calculated by multiplying the bus width by the speed of its memory. If the card has DDR RAM, it should be multiplied by 2 once again. If DDR5, multiply by 4 instead. The better the memory bandwidth, the faster the card will be in general. It especially helps with AA, High Dynamic Range and high resolutions.

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

Pixel Rate: Pixel rate is the most pixels that the graphics card could possibly record to the local memory per 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 - aka Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel rate also depends on many other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the potential to get to the max fill rate.