Radeon HD 5870 vs Radeon HD 7870 XT

Intro

Compare that to the Radeon HD 7870 XT, which has a clock speed of 925 MHz and a GDDR5 memory speed of 1500 MHz. It also features a 256-bit memory 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 5870		188 Watts
	Difference: 3 Watts (2%)

Memory Bandwidth

Performance-wise, the Radeon HD 7870 XT should theoretically be much superior to the Radeon HD 5870 overall. (explain)

Radeon HD 7870 XT		192000 MB/sec
Radeon HD 5870		153600 MB/sec
	Difference: 38400 (25%)

Texel Rate

The Radeon HD 7870 XT is much (approximately 31%) better at anisotropic filtering than the Radeon HD 5870. (explain)

Radeon HD 7870 XT		88800 Mtexels/sec
Radeon HD 5870		68000 Mtexels/sec
	Difference: 20800 (31%)

Pixel Rate

If running with lots of anti-aliasing is important to you, then the Radeon HD 7870 XT is superior to the Radeon HD 5870, but it probably won't make a huge difference. (explain)

Radeon HD 7870 XT		29600 Mpixels/sec
Radeon HD 5870		27200 Mpixels/sec
	Difference: 2400 (9%)

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 largest amount of information (counted in MB per second) that can be moved over the external memory interface in a second. It is calculated by multiplying the card's bus width by its memory clock speed. In the case of DDR RAM, the result should be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The better the card's memory bandwidth, 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 texture map elements (texels) that are processed in one second. This figure is worked out by multiplying the total texture units by the core clock speed of the chip. The higher this number, the better the video card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed per second.

Pixel Rate: Pixel rate is the maximum amount of pixels the video card could possibly record to its local memory per second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the amount of Render Output Units by the the core 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 lots of other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to reach the maximum fill rate.