Radeon HD 6770 1GB vs Radeon HD 7770

Intro

Compare all that to the Radeon HD 7770, which comes with core clock speeds of 1000 MHz on the GPU, and 1125 MHz on the 1024 MB of GDDR5 RAM. It features 640 SPUs along with 40 TAUs and 16 Rasterization Operator Units.

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 be a bit faster than the Radeon HD 6770 1GB in general. (explain)

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

Texel Rate

The Radeon HD 7770 will be just a bit (approximately 11%) more effective at anisotropic filtering 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 running with a high screen resolution is important to you, then the Radeon HD 7770 is the winner, not by a very large margin though. (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: Memory bandwidth is the maximum amount of data (counted in MB per second) that can be transferred over the external memory interface in a second. It's worked out by multiplying the bus width by its memory clock speed. If it uses DDR memory, it must be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The better 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 texture map elements (texels) that are processed per second. This figure is calculated by multiplying the total amount of texture units by the core speed of the chip. The higher the texel rate, the better the card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in a second.

Pixel Rate: Pixel rate is the most pixels the video card could 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 clock speed of the card. ROPs (Raster Operations Pipelines - also sometimes called 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 - the lower the bandwidth is, the lower the potential to get to the maximum fill rate.