Radeon HD 4770 vs Radeon HD 6850

Intro

Compare those specifications to the Radeon HD 6850, which uses a 40 nm design. AMD has set the core frequency at 775 MHz. The GDDR5 memory runs at a speed of 1000 MHz on this particular card. It features 960 SPUs as well as 48 Texture Address Units and 32 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4770		80 Watts
Radeon HD 6850		127 Watts
	Difference: 47 Watts (59%)

Memory Bandwidth

The Radeon HD 6850 should theoretically be much faster than the Radeon HD 4770 in general. (explain)

Radeon HD 6850		128000 MB/sec
Radeon HD 4770		51200 MB/sec
	Difference: 76800 (150%)

Texel Rate

The Radeon HD 6850 is quite a bit (about 55%) better at texture filtering than the Radeon HD 4770. (explain)

Radeon HD 6850		37200 Mtexels/sec
Radeon HD 4770		24000 Mtexels/sec
	Difference: 13200 (55%)

Pixel Rate

The Radeon HD 6850 is a lot (approximately 107%) better at anti-aliasing than the Radeon HD 4770, and should be capable of handling higher resolutions better. (explain)

Radeon HD 6850		24800 Mpixels/sec
Radeon HD 4770		12000 Mpixels/sec
	Difference: 12800 (107%)

Please note that the above 'benchmarks' are all just theoretical - the results were calculated based on the card's specifications, and real-world performance may (and probably will) vary at least a bit.

Price Comparison

Specifications

Memory Bandwidth: Bandwidth is the maximum amount of information (counted in MB per second) that can be transported past the external memory interface in one second. It's calculated by multiplying the bus width by its memory clock speed. In the case of DDR RAM, the result should be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The higher the bandwidth is, the faster the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and higher screen resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are processed in one second. This figure is worked out by multiplying the total texture units of the card by the core speed of the chip. The higher the texel rate, 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 maximum number of pixels the video card can possibly record to its local memory in one second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the amount of ROPs by the clock speed of the card. 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 is also dependant on quite a few other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to get to the maximum fill rate.