Radeon HD 6870 vs Radeon R5 M255

Intro

Compare those specifications to the Radeon R5 M255, which features core 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 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Memory Bandwidth

Performance-wise, the Radeon HD 6870 should theoretically be a lot better than the Radeon R5 M255 in general. (explain)

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

Texel Rate

The Radeon HD 6870 will be much (more or less 168%) more effective at anisotropic filtering than the Radeon R5 M255. (explain)

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

Pixel Rate

The Radeon HD 6870 is quite a bit (approximately 283%) better at FSAA than the Radeon R5 M255, and also will be able to handle higher resolutions without slowing down too much. (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 largest amount of information (counted in MB per second) that can be transported past the external memory interface within a second. It is worked out by multiplying the bus width by its memory speed. In the case of DDR memory, it must be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The better the bandwidth is, the faster the card will be in general. It especially helps with AA, High Dynamic Range and high resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are applied 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 this number, the better the card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied per second.

Pixel Rate: Pixel rate is the maximum amount of pixels the video card can possibly record to its local memory in a second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the number of colour ROPs 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 output rate also depends on quite a few other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the ability to get to the max fill rate.