Radeon HD 6870 vs Radeon HD 7950 3GB

Intro

Compare those specifications to the Radeon HD 7950 3GB, which has a clock frequency of 800 MHz and a GDDR5 memory frequency of 1250 MHz. It also features a 384-bit memory bus, and makes use of a 28 nm design. It features 1792 SPUs, 112 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 6870		151 Watts
Radeon HD 7950 3GB		200 Watts
	Difference: 49 Watts (32%)

Memory Bandwidth

Theoretically speaking, the Radeon HD 7950 3GB is 79% quicker than the Radeon HD 6870 in general, due to its higher data rate. (explain)

Radeon HD 7950 3GB		240000 MB/sec
Radeon HD 6870		134400 MB/sec
	Difference: 105600 (79%)

Texel Rate

The Radeon HD 7950 3GB should be a lot (more or less 78%) more effective at texture filtering than the Radeon HD 6870. (explain)

Radeon HD 7950 3GB		89600 Mtexels/sec
Radeon HD 6870		50400 Mtexels/sec
	Difference: 39200 (78%)

Pixel Rate

If using lots of anti-aliasing is important to you, then the Radeon HD 6870 is superior to the Radeon HD 7950 3GB, though not by far. (explain)

Radeon HD 6870		28800 Mpixels/sec
Radeon HD 7950 3GB		25600 Mpixels/sec
	Difference: 3200 (13%)

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 data (counted in MB per second) that can be transported over the external memory interface in one second. It's calculated by multiplying the card's interface width by the speed of its memory. If the card has DDR 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, HDR and higher screen 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 number of texture units 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 applied in one second.

Pixel Rate: Pixel rate is the most pixels the video card can possibly write to the local memory in a second - measured in millions of pixels per second. The number is calculated by multiplying the number of Render Output Units by the clock speed of the card. ROPs (Raster Operations Pipelines - sometimes also referred to as 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, most notably the memory bandwidth - the lower the bandwidth is, the lower the ability to get to the maximum fill rate.