Radeon HD 7870 XT vs Radeon HD 7950 3GB

Intro

Compare those specs to the Radeon HD 7950 3GB, which has core clock speeds of 800 MHz on the GPU, and 1250 MHz on the 3072 MB of GDDR5 memory. It features 1792 SPUs as well as 112 TAUs 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

Theoretically speaking, the Radeon HD 7950 3GB should be a lot 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 should be a small bit (about 1%) better at AF 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

The Radeon HD 7870 XT should be a little bit (more or less 16%) faster with regards to full screen anti-aliasing than the Radeon HD 7950 3GB, and will be capable of handling higher screen resolutions better. (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 information (in units of MB per second) that can be transported across the external memory interface within a second. The number is calculated by multiplying the card's interface width by the speed of its memory. In the case of DDR type RAM, it must be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The better the bandwidth is, the better the card will be in general. It especially helps with AA, HDR and high resolutions.

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

Pixel Rate: Pixel rate is the maximum number of pixels that the graphics card can possibly write to its local memory in a second - measured in millions of pixels per second. The number is worked out by multiplying the amount of Render Output Units by the the card's clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel output rate also depends on many other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the ability to get to the maximum fill rate.