Radeon HD 6990 vs Radeon R9 M390X

Intro

Compare all that to the Radeon R9 M390X, which features a GPU core clock speed of 723 MHz, and 4096 MB of GDDR5 RAM set to run at 1250 MHz through a 256-bit bus. It also 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 M390X		125 Watts
Radeon HD 6990		375 Watts
	Difference: 250 Watts (200%)

Memory Bandwidth

As far as performance goes, the Radeon HD 6990 should theoretically be much superior to the Radeon R9 M390X overall. (explain)

Radeon HD 6990		320000 MB/sec
Radeon R9 M390X		160000 MB/sec
	Difference: 160000 (100%)

Texel Rate

The Radeon HD 6990 is a lot (approximately 72%) more effective at AF than the Radeon R9 M390X. (explain)

Radeon HD 6990		159360 Mtexels/sec
Radeon R9 M390X		92544 Mtexels/sec
	Difference: 66816 (72%)

Pixel Rate

If running with a high screen resolution is important to you, then the Radeon HD 6990 is superior to the Radeon R9 M390X, by far. (explain)

Radeon HD 6990		53120 Mpixels/sec
Radeon R9 M390X		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: Bandwidth is the largest amount of information (in units of megabytes per second) that can be moved past the external memory interface in one second. It is calculated by multiplying the card's bus width by its memory clock speed. If the card has DDR memory, it should be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The higher the memory bandwidth, the faster the card will be in general. It especially helps with AA, HDR and high resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that can be applied per second. This is worked out by multiplying the total amount of texture units by the core clock speed of the chip. The higher the texel rate, the better the card will be at handling 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 can possibly record to the local memory in a second - measured in millions of pixels per second. The number is calculated by multiplying the number of Raster Operations Pipelines by the the core clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel rate is also dependant on quite a few other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to reach the maximum fill rate.