Radeon HD 5870 vs Radeon HD 7870

Intro

Compare those specs 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 bus, and uses a 28 nm design. It is made up 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 exactly the same bandwidth, so in theory they should have the same performance. (explain)

Texel Rate

The Radeon HD 7870 should be a bit (approximately 18%) faster with regards to 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

If using a high resolution is important to you, then the Radeon HD 7870 is the winner, but it probably won't make a huge difference. (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: Bandwidth is the largest amount of data (in units of megabytes per second) that can be transported past the external memory interface within a second. It's calculated by multiplying the bus width by its memory speed. If it uses DDR RAM, it should be multiplied by 2 once again. If DDR5, multiply by 4 instead. The higher the bandwidth is, 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 can be applied in one second. This figure is worked out by multiplying the total texture units of the card by the core speed of the chip. The better this number, the better the graphics card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels in a second.

Pixel Rate: Pixel rate is the maximum number of pixels that the graphics chip can possibly write to the local memory in a second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the amount of Raster Operations Pipelines by the the card's clock speed. ROPs (Raster Operations Pipelines - sometimes also referred to as 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, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to reach the maximum fill rate.