Radeon HD 4770 vs Radeon HD 6850

Intro

Compare those specs to the Radeon HD 6850, which has core speeds of 775 MHz on the GPU, and 1000 MHz on the 1024 MB of GDDR5 RAM. 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

In theory, the Radeon HD 6850 will be 150% quicker than the Radeon HD 4770 in general, due to its higher bandwidth. (explain)

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

Texel Rate

The Radeon HD 6850 is a lot (approximately 55%) faster with regards to AF 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 (about 107%) more effective at AA than the Radeon HD 4770, and will be able to handle higher screen resolutions while still performing well. (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: Memory bandwidth is the max amount of information (measured in megabytes per second) that can be moved across the external memory interface in one second. The number is worked out by multiplying the card's interface width by the speed of its memory. In the case of DDR type RAM, it must be multiplied by 2 again. If DDR5, multiply by 4 instead. The higher the memory bandwidth, 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 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 higher this number, the better the 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 the video card could possibly write to its local memory in one second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the amount of ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel rate is also dependant on many other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the potential to get to the maximum fill rate.