Radeon HD 6990 vs Radeon R5 M255

Intro

Compare those specifications to the Radeon R5 M255, which uses a 28 nm design. AMD has set the core frequency at 940 MHz. The DDR3 RAM is set to run at a frequency of 1000 MHz on this specific model. It features 320 SPUs along with 20 TAUs and 8 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Memory Bandwidth

Performance-wise, the Radeon HD 6990 should in theory be a lot superior to the Radeon R5 M255 overall. (explain)

Radeon HD 6990		320000 MB/sec
Radeon R5 M255		16000 MB/sec
	Difference: 304000 (1900%)

Texel Rate

The Radeon HD 6990 will be quite a bit (more or less 748%) faster with regards to texture filtering than the Radeon R5 M255. (explain)

Radeon HD 6990		159360 Mtexels/sec
Radeon R5 M255		18800 Mtexels/sec
	Difference: 140560 (748%)

Pixel Rate

If running with lots of anti-aliasing is important to you, then the Radeon HD 6990 is superior to the Radeon R5 M255, by a large margin. (explain)

Radeon HD 6990		53120 Mpixels/sec
Radeon R5 M255		7520 Mpixels/sec
	Difference: 45600 (606%)

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.

One or more cards in this comparison are multi-core. This means that their bandwidth, texel and pixel rates are theoretically doubled - this does not mean the card will actually perform twice as fast, but only that it should in theory be able to. Actual game benchmarks will give a more accurate idea of what it's capable of.

Price Comparison

Specifications

Memory Bandwidth: Memory bandwidth is the maximum amount of information (counted in MB per second) that can be transported across the external memory interface in one second. It's calculated by multiplying the bus width by its memory speed. If the card has DDR type memory, it should be multiplied by 2 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 number of texture map elements (texels) that are processed per second. This figure is calculated by multiplying the total texture units of the card by the core speed of the chip. The better the texel rate, the better the graphics card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in a second.

Pixel Rate: Pixel rate is the most pixels the video card could possibly record to the local memory in one second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the number of colour ROPs by the the core speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel rate is also dependant on lots of other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the ability to get to the max fill rate.