Radeon HD 6990 vs Radeon R9 M295X

Intro

Compare all of that to the Radeon R9 M295X, which comes with a clock speed of 750 MHz and a GDDR5 memory speed of 1375 MHz. It also makes use of a 256-bit memory bus, and uses a 28 nm design. It is comprised of 2048 SPUs, 128 Texture Address Units, and 32 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon R9 M295X		125 Watts
Radeon HD 6990		375 Watts
	Difference: 250 Watts (200%)

Memory Bandwidth

Theoretically speaking, the Radeon HD 6990 is 82% quicker than the Radeon R9 M295X overall, due to its higher bandwidth. (explain)

Radeon HD 6990		320000 MB/sec
Radeon R9 M295X		176000 MB/sec
	Difference: 144000 (82%)

Texel Rate

The Radeon HD 6990 is much (more or less 66%) faster with regards to anisotropic filtering than the Radeon R9 M295X. (explain)

Radeon HD 6990		159360 Mtexels/sec
Radeon R9 M295X		96000 Mtexels/sec
	Difference: 63360 (66%)

Pixel Rate

The Radeon HD 6990 is much (more or less 121%) better at AA than the Radeon R9 M295X, and also should be capable of handling higher resolutions without losing too much performance. (explain)

Radeon HD 6990		53120 Mpixels/sec
Radeon R9 M295X		24000 Mpixels/sec
	Difference: 29120 (121%)

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: Bandwidth is the max amount of information (measured in MB per second) that can be transferred past the external memory interface within a second. It is calculated by multiplying the bus width by the speed of its memory. In the case of DDR memory, it must be multiplied by 2 again. If DDR5, multiply by 4 instead. The higher the card's 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 processed in one second. This figure is calculated by multiplying the total number of texture units by the core speed of the chip. The better this number, the better the video card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in a second.

Pixel Rate: Pixel rate is the maximum amount of pixels the video card can possibly write to its local memory in a second - measured in millions of pixels per second. The number is worked out by multiplying the amount of Render Output Units by the the core clock speed. 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 many other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the potential to get to the max fill rate.