Radeon HD 7870 vs Radeon R5 M255

Intro

Compare all that to the Radeon R5 M255, which comes with core clock speeds of 940 MHz on the GPU, and 1000 MHz on the 2048 MB of DDR3 memory. It features 320 SPUs along with 20 Texture Address Units and 8 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Memory Bandwidth

The Radeon HD 7870, in theory, should perform a lot faster than the Radeon R5 M255 in general. (explain)

Radeon HD 7870		153600 MB/sec
Radeon R5 M255		16000 MB/sec
	Difference: 137600 (860%)

Texel Rate

The Radeon HD 7870 should be quite a bit (more or less 326%) more effective at texture filtering than the Radeon R5 M255. (explain)

Radeon HD 7870		80000 Mtexels/sec
Radeon R5 M255		18800 Mtexels/sec
	Difference: 61200 (326%)

Pixel Rate

If using high levels of AA is important to you, then the Radeon HD 7870 is superior to the Radeon R5 M255, by far. (explain)

Radeon HD 7870		32000 Mpixels/sec
Radeon R5 M255		7520 Mpixels/sec
	Difference: 24480 (326%)

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 maximum amount of information (in units of MB 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. In the case of DDR type RAM, it must be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The better the memory bandwidth, the better 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 applied per second. This is worked out by multiplying the total texture units of the card by the core speed of the chip. The better the texel rate, the better the video card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied per second.

Pixel Rate: Pixel rate is the maximum number of pixels the video card can possibly write to its local memory in one second - measured in millions of pixels per second. The figure is worked out by multiplying the amount of Render Output Units by the clock speed of the card. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel rate is also dependant on many other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the potential to reach the max fill rate.