Radeon HD 6770 1GB vs Radeon HD 6870

Intro

Compare those specifications to the Radeon HD 6870, which uses a 40 nm design. AMD has set the core frequency at 900 MHz. The GDDR5 RAM is set to run at a frequency of 1050 MHz on this model. It features 1120 SPUs along with 56 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 6770 1GB		108 Watts
Radeon HD 6870		151 Watts
	Difference: 43 Watts (40%)

Memory Bandwidth

The Radeon HD 6870 should theoretically perform much faster than the Radeon HD 6770 1GB overall. (explain)

Radeon HD 6870		134400 MB/sec
Radeon HD 6770 1GB		67200 MB/sec
	Difference: 67200 (100%)

Texel Rate

The Radeon HD 6870 is quite a bit (about 40%) faster with regards to texture filtering than the Radeon HD 6770 1GB. (explain)

Radeon HD 6870		50400 Mtexels/sec
Radeon HD 6770 1GB		36000 Mtexels/sec
	Difference: 14400 (40%)

Pixel Rate

The Radeon HD 6870 is a lot (approximately 100%) faster with regards to anti-aliasing than the Radeon HD 6770 1GB, and also should be capable of handling higher resolutions more effectively. (explain)

Radeon HD 6870		28800 Mpixels/sec
Radeon HD 6770 1GB		14400 Mpixels/sec
	Difference: 14400 (100%)

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 data (measured in megabytes per second) that can be transported across the external memory interface in a second. It's worked out by multiplying the card's bus width by its memory clock speed. In the case of DDR type memory, the result should be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The higher the card's memory bandwidth, the better the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that are processed per second. This is calculated by multiplying the total amount of texture units of the card by the core clock speed of the chip. The better this number, the better the graphics card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels in one second.

Pixel Rate: Pixel rate is the most pixels that the graphics chip could possibly record to its local memory per second - measured in millions of pixels per second. The number is calculated by multiplying the number of Raster Operations Pipelines 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 quite a few other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the ability to get to the max fill rate.