Radeon HD 6870 vs Radeon R5 M255

Intro

Compare that to the Radeon R5 M255, which has a GPU core clock speed of 940 MHz, and 2048 MB of DDR3 memory set to run at 1000 MHz through a 64-bit bus. It also features 320 SPUs, 20 TAUs, and 8 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Memory Bandwidth

As far as performance goes, the Radeon HD 6870 should in theory be quite a bit superior to the Radeon R5 M255 overall. (explain)

Radeon HD 6870		134400 MB/sec
Radeon R5 M255		16000 MB/sec
	Difference: 118400 (740%)

Texel Rate

The Radeon HD 6870 should be much (about 168%) more effective at texture filtering than the Radeon R5 M255. (explain)

Radeon HD 6870		50400 Mtexels/sec
Radeon R5 M255		18800 Mtexels/sec
	Difference: 31600 (168%)

Pixel Rate

If using high levels of AA is important to you, then the Radeon HD 6870 is a better choice, by a large margin. (explain)

Radeon HD 6870		28800 Mpixels/sec
Radeon R5 M255		7520 Mpixels/sec
	Difference: 21280 (283%)

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 (measured in megabytes per second) that can be transported past the external memory interface within a second. It's calculated by multiplying the interface width by its memory clock speed. If it uses DDR type RAM, the result should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The higher the bandwidth is, the faster the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and high resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that can be processed in one second. This number is worked out by multiplying the total amount of texture units of the card by the core clock speed of the chip. The higher the texel rate, the better the graphics card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in a second.

Pixel Rate: Pixel rate is the maximum number of pixels that the graphics chip could possibly record to the local memory in one second - measured in millions of pixels per second. Pixel rate is calculated 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 filling the screen with pixels (the image). The actual pixel rate is also dependant on quite a few other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to reach the max fill rate.