Radeon HD 6950 2GB vs Radeon HD 7870 XT

Intro

Compare all of that to the Radeon HD 7870 XT, which comes with a core clock frequency of 925 MHz and a GDDR5 memory frequency of 1500 MHz. It also uses a 256-bit bus, and makes use of a 28 nm design. It features 1536 SPUs, 96 Texture Address Units, and 32 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 7870 XT		185 Watts
Radeon HD 6950 2GB		200 Watts
	Difference: 15 Watts (8%)

Memory Bandwidth

Theoretically speaking, the Radeon HD 7870 XT should be 20% quicker than the Radeon HD 6950 2GB in general, due to its greater data rate. (explain)

Radeon HD 7870 XT		192000 MB/sec
Radeon HD 6950 2GB		160000 MB/sec
	Difference: 32000 (20%)

Texel Rate

The Radeon HD 7870 XT should be a lot (more or less 26%) better at anisotropic filtering than the Radeon HD 6950 2GB. (explain)

Radeon HD 7870 XT		88800 Mtexels/sec
Radeon HD 6950 2GB		70400 Mtexels/sec
	Difference: 18400 (26%)

Pixel Rate

The Radeon HD 7870 XT will be a bit (about 16%) faster with regards to AA than the Radeon HD 6950 2GB, and should be capable of handling higher screen resolutions more effectively. (explain)

Radeon HD 7870 XT		29600 Mpixels/sec
Radeon HD 6950 2GB		25600 Mpixels/sec
	Difference: 4000 (16%)

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 information (in units of megabytes per second) that can be transported across the external memory interface within a second. It's calculated by multiplying the card's bus width by its memory speed. If it uses DDR type RAM, it should be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The higher the bandwidth is, 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 in one second. This is worked out by multiplying the total amount of texture units of the card by the core speed of the chip. The better this number, the better the card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in one second.

Pixel Rate: Pixel rate is the maximum amount of pixels the graphics card could possibly write to the local memory in one second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the amount of colour ROPs by the clock speed of the card. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for outputting the pixels (image) to the screen. 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 reach the max fill rate.