Radeon HD 6770 1GB vs Radeon HD 7770

Intro

Compare all of that to the Radeon HD 7770, which has GPU clock speed of 1000 MHz, and 1024 MB of GDDR5 RAM running at 1125 MHz through a 128-bit bus. It also is comprised of 640 SPUs, 40 Texture Address Units, and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 7770		80 Watts
Radeon HD 6770 1GB		108 Watts
	Difference: 28 Watts (35%)

Memory Bandwidth

In theory, the Radeon HD 7770 should perform a little bit faster than the Radeon HD 6770 1GB overall. (explain)

Radeon HD 7770		72000 MB/sec
Radeon HD 6770 1GB		67200 MB/sec
	Difference: 4800 (7%)

Texel Rate

The Radeon HD 7770 should be a bit (more or less 11%) better at AF than the Radeon HD 6770 1GB. (explain)

Radeon HD 7770		40000 Mtexels/sec
Radeon HD 6770 1GB		36000 Mtexels/sec
	Difference: 4000 (11%)

Pixel Rate

If using lots of anti-aliasing is important to you, then the Radeon HD 7770 is superior to the Radeon HD 6770 1GB, but not by far. (explain)

Radeon HD 7770		16000 Mpixels/sec
Radeon HD 6770 1GB		14400 Mpixels/sec
	Difference: 1600 (11%)

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 largest amount of information (measured in MB per second) that can be transported over the external memory interface in one second. It's calculated by multiplying the card's bus width by its memory speed. In the case of DDR type memory, it must be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The better the card's memory bandwidth, the better the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and high resolutions.

Texel Rate: Texel rate is the maximum amount 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 clock speed of the chip. The better the texel rate, the better the video card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in one second.

Pixel Rate: Pixel rate is the most pixels that the graphics card can possibly write to the local memory in one second - measured in millions of pixels per second. The figure is calculated 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 outputting the pixels (image) to the screen. The actual pixel rate also depends on many other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to reach the max fill rate.