Radeon HD 3850 256MB vs Radeon HD 6790

Intro

The Radeon HD 3850 256MB makes use of a 55 nm design. AMD has set the core frequency at 668 MHz. The GDDR3 memory is set to run at a frequency of 828 MHz on this card. It features 320(64x5) SPUs along with 16 Texture Address Units and 16 Rasterization Operator Units.

Compare that to the Radeon HD 6790, which comes with core clock speeds of 840 MHz on the GPU, and 1050 MHz on the 1024 MB of GDDR5 RAM. It features 800 SPUs as well as 40 Texture Address Units and 16 Rasterization Operator Units.

Price Comparison

Specifications

Memory Bandwidth: Bandwidth is the max amount of data (counted in MB per second) that can be transported past the external memory interface within a second. It's calculated by multiplying the card's interface width by its memory clock speed. If it uses DDR type RAM, the result should be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The better the bandwidth is, 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 amount of texture map elements (texels) that can be applied per second. This is worked out 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 in one second.

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