Radeon HD 4770 vs Radeon HD 6770

Intro

Compare those specs to the Radeon HD 6770, which has a clock speed of 900 MHz and a GDDR5 memory frequency of 1050 MHz. It also makes use of a 128-bit bus, and makes use of a 40 nm design. It is comprised of 800 SPUs, 40 TAUs, and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4770		80 Watts
Radeon HD 6770		108 Watts
	Difference: 28 Watts (35%)

Memory Bandwidth

The Radeon HD 6770, in theory, should be a lot faster than the Radeon HD 4770 in general. (explain)

Radeon HD 6770		67200 MB/sec
Radeon HD 4770		51200 MB/sec
	Difference: 16000 (31%)

Texel Rate

The Radeon HD 6770 is quite a bit (more or less 50%) better at AF than the Radeon HD 4770. (explain)

Radeon HD 6770		36000 Mtexels/sec
Radeon HD 4770		24000 Mtexels/sec
	Difference: 12000 (50%)

Pixel Rate

If running with lots of anti-aliasing is important to you, then the Radeon HD 6770 is the winner, not by a very large margin though. (explain)

Radeon HD 6770		14400 Mpixels/sec
Radeon HD 4770		12000 Mpixels/sec
	Difference: 2400 (20%)

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 max amount of data (counted in MB per second) that can be transferred over the external memory interface within a second. The number is worked out by multiplying the bus width by its memory speed. If it uses DDR RAM, the result should be multiplied by 2 once again. If DDR5, multiply by 4 instead. The higher the card's 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 can be applied per second. This figure is calculated by multiplying the total amount of 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 handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in a second.

Pixel Rate: Pixel rate is the most pixels the video card could possibly record to its local memory per second - measured in millions of pixels per second. The figure is calculated by multiplying the amount of colour ROPs by the clock speed of the card. ROPs (Raster Operations Pipelines - aka 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 - the lower the bandwidth is, the lower the potential to reach the maximum fill rate.