Radeon HD 6770 1GB vs Radeon HD 6870

Intro

Compare those specs to the Radeon HD 6870, which features a clock frequency of 900 MHz and a GDDR5 memory speed of 1050 MHz. It also features a 256-bit memory bus, and uses a 40 nm design. It features 1120 SPUs, 56 Texture Address Units, and 32 ROPs.

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

Theoretically speaking, the Radeon HD 6870 will be 100% faster than the Radeon HD 6770 1GB overall, due to its greater data rate. (explain)

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

Texel Rate

The Radeon HD 6870 should be a lot (about 40%) faster with regards to anisotropic 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 should be quite a bit (more or less 100%) faster with regards to anti-aliasing than the Radeon HD 6770 1GB, and 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: Memory bandwidth is the max amount of data (counted in megabytes per second) that can be moved past the external memory interface in a second. It's calculated by multiplying the interface width by its memory clock speed. If it uses DDR type memory, it should be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The higher the memory bandwidth, the faster the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and higher screen resolutions.

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

Pixel Rate: Pixel rate is the maximum amount of pixels the graphics card could possibly write to its local memory in one second - measured in millions of pixels per second. The number is worked out by multiplying the number of Render Output Units by the clock speed of the card. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel output rate is also dependant on quite a few other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to get to the maximum fill rate.