Radeon HD 6990 vs Radeon R9 M395X

Intro

Compare those specs to the Radeon R9 M395X, which comes with core clock speeds of 723 MHz on the GPU, and 1250 MHz on the 4096 MB of GDDR5 RAM. It features 2048 SPUs along with 128 Texture Address Units and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon R9 M395X		125 Watts
Radeon HD 6990		375 Watts
	Difference: 250 Watts (200%)

Memory Bandwidth

The Radeon HD 6990, in theory, should perform much faster than the Radeon R9 M395X overall. (explain)

Radeon HD 6990		320000 MB/sec
Radeon R9 M395X		160000 MB/sec
	Difference: 160000 (100%)

Texel Rate

The Radeon HD 6990 should be much (more or less 72%) more effective at texture filtering than the Radeon R9 M395X. (explain)

Radeon HD 6990		159360 Mtexels/sec
Radeon R9 M395X		92544 Mtexels/sec
	Difference: 66816 (72%)

Pixel Rate

If using high levels of AA is important to you, then the Radeon HD 6990 is a better choice, by far. (explain)

Radeon HD 6990		53120 Mpixels/sec
Radeon R9 M395X		23136 Mpixels/sec
	Difference: 29984 (130%)

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 (measured in megabytes per second) that can be transported over the external memory interface within a second. The number is worked out by multiplying the card's bus width by the speed of its memory. If it uses DDR type memory, the result should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The better the card's memory bandwidth, the better the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and higher screen resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that are applied in one second. This 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 card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels in one second.

Pixel Rate: Pixel rate is the maximum amount of pixels the graphics card can possibly write 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 the core clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel rate also depends on lots of other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to get to the maximum fill rate.