Radeon HD 7870 XT vs Radeon HD 7950 3GB

Intro

Compare that to the Radeon HD 7950 3GB, which has a core clock frequency of 800 MHz and a GDDR5 memory speed of 1250 MHz. It also uses a 384-bit bus, and uses a 28 nm design. It is made up of 1792 SPUs, 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

In theory, the Radeon HD 7950 3GB should be 25% faster than the Radeon HD 7870 XT in general, due to its higher data rate. (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 will be a small bit (more or less 1%) more effective 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 will be a small bit (about 16%) more effective at AA than the Radeon HD 7950 3GB, and also will be able to handle higher resolutions more effectively. (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: Bandwidth is the max amount of data (in units of MB per second) that can be transported past the external memory interface in a second. It's worked out by multiplying the bus width by its memory clock speed. If the card has DDR RAM, it must be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The higher the bandwidth is, the better 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 amount of texture map elements (texels) that can be processed in one second. This is worked out by multiplying the total amount of texture units of the card by the core clock 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 in one second.

Pixel Rate: Pixel rate is the most pixels the graphics card could possibly write to the local memory in one second - measured in millions of pixels per second. The number is worked out by multiplying the amount of ROPs by the the core speed of the card. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel rate also depends on quite a few other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to reach the maximum fill rate.