Radeon HD 5870 vs Radeon HD 7870 XT

Intro

Compare all that to the Radeon HD 7870 XT, which features a clock frequency of 925 MHz and a GDDR5 memory frequency of 1500 MHz. It also uses a 256-bit bus, and uses a 28 nm design. It is made up of 1536 SPUs, 96 TAUs, 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 in theory be quite a bit superior to the Radeon HD 5870 in general. (explain)

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

Texel Rate

The Radeon HD 7870 XT should be a lot (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 a high resolution is important to you, then the Radeon HD 7870 XT is a better choice, but only just. (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 data (in units of megabytes per second) that can be transported past the external memory interface in one second. It's worked out by multiplying the card's bus width by the speed of its memory. In the case of DDR type RAM, it must be multiplied by 2 once again. If DDR5, multiply by 4 instead. The better the card's memory bandwidth, the faster the card will be in general. It especially helps with AA, High Dynamic Range and higher screen resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that are processed per second. This is calculated by multiplying the total texture units by the core speed of the chip. The better the texel rate, the better the card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels per second.

Pixel Rate: Pixel rate is the most pixels that the graphics chip can possibly write to the local memory in one second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the number of ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel output rate is also dependant on lots of other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the ability to reach the max fill rate.