Radeon HD 7870 XT vs Radeon HD 7950 3GB

Intro

Compare those specs to the Radeon HD 7950 3GB, which makes use of a 28 nm design. AMD has clocked the core frequency at 800 MHz. The GDDR5 RAM is set to run at a frequency of 1250 MHz on this particular model. It features 1792 SPUs along with 112 Texture Address Units and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 7870 XT		185 Watts
Radeon HD 7950 3GB		200 Watts
	Difference: 15 Watts (8%)

Memory Bandwidth

The Radeon HD 7950 3GB should theoretically be quite a bit faster than the Radeon HD 7870 XT overall. (explain)

Radeon HD 7950 3GB		240000 MB/sec
Radeon HD 7870 XT		192000 MB/sec
	Difference: 48000 (25%)

Texel Rate

The Radeon HD 7950 3GB is just a bit (more or less 1%) better at texture filtering than the Radeon HD 7870 XT. (explain)

Radeon HD 7950 3GB		89600 Mtexels/sec
Radeon HD 7870 XT		88800 Mtexels/sec
	Difference: 800 (1%)

Pixel Rate

If using a high resolution is important to you, then the Radeon HD 7870 XT is superior to the Radeon HD 7950 3GB, but not by far. (explain)

Radeon HD 7870 XT		29600 Mpixels/sec
Radeon HD 7950 3GB		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 data (measured in MB per second) that can be transferred past the external memory interface within a second. It is worked out by multiplying the bus width by its memory speed. In the case of DDR type memory, it must be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The better the bandwidth is, 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 number of texture map elements (texels) that are applied per second. This is calculated by multiplying the total texture units of the card by the core clock speed of the chip. The higher this number, the better the card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in one second.

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