Radeon HD 7870 XT vs Radeon R5 M255

Intro

Compare those specs to the Radeon R5 M255, which makes use of a 28 nm design. AMD has set the core speed at 940 MHz. The DDR3 memory runs at a frequency of 1000 MHz on this particular card. It features 320 SPUs along with 20 TAUs and 8 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Memory Bandwidth

The Radeon HD 7870 XT should theoretically be much faster than the Radeon R5 M255 in general. (explain)

Radeon HD 7870 XT		192000 MB/sec
Radeon R5 M255		16000 MB/sec
	Difference: 176000 (1100%)

Texel Rate

The Radeon HD 7870 XT will be quite a bit (approximately 372%) more effective at texture filtering than the Radeon R5 M255. (explain)

Radeon HD 7870 XT		88800 Mtexels/sec
Radeon R5 M255		18800 Mtexels/sec
	Difference: 70000 (372%)

Pixel Rate

The Radeon HD 7870 XT will be a lot (about 294%) more effective at anti-aliasing than the Radeon R5 M255, and should be capable of handling higher screen resolutions without losing too much performance. (explain)

Radeon HD 7870 XT		29600 Mpixels/sec
Radeon R5 M255		7520 Mpixels/sec
	Difference: 22080 (294%)

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 max amount of data (counted in MB per second) that can be transported across the external memory interface within a second. It's calculated by multiplying the card's bus width by its memory clock speed. If it uses DDR RAM, it should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The better 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 are applied in one second. This number is worked out by multiplying the total number of texture units by the core clock speed of the chip. The higher this number, the better the graphics 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 maximum number of pixels the graphics card could possibly record to its local memory per second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the number of Render Output Units by the the card's clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel fill rate is also dependant on quite a few other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the potential to get to the max fill rate.