Radeon HD 5870 vs Radeon HD 7870

Intro

Compare all that to the Radeon HD 7870, which features a clock speed of 1000 MHz and a GDDR5 memory frequency of 1200 MHz. It also uses a 256-bit memory bus, and makes use of a 28 nm design. It is comprised of 1280 SPUs, 80 TAUs, and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 7870		175 Watts
Radeon HD 5870		188 Watts
	Difference: 13 Watts (7%)

Memory Bandwidth

Both cards have the exact same memory bandwidth, so theoretically they should have identical performance. (explain)

Texel Rate

The Radeon HD 7870 will be a bit (more or less 18%) better at anisotropic filtering than the Radeon HD 5870. (explain)

Radeon HD 7870		80000 Mtexels/sec
Radeon HD 5870		68000 Mtexels/sec
	Difference: 12000 (18%)

Pixel Rate

The Radeon HD 7870 should be a bit (about 18%) more effective at FSAA than the Radeon HD 5870, and should be capable of handling higher screen resolutions without losing too much performance. (explain)

Radeon HD 7870		32000 Mpixels/sec
Radeon HD 5870		27200 Mpixels/sec
	Difference: 4800 (18%)

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 (counted in megabytes per second) that can be moved over the external memory interface within a second. It is worked out by multiplying the card's bus width by its memory clock speed. If it uses DDR type memory, it must be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The higher the memory bandwidth, the faster the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that are applied in one second. This is calculated by multiplying the total number 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 texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed per second.

Pixel Rate: Pixel rate is the most pixels the graphics card could possibly record to the local memory in one second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the amount of ROPs by the the card's 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, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to get to the maximum fill rate.