Radeon HD 6990 vs Radeon R9 M390X

Intro

Compare all of that to the Radeon R9 M390X, which comes with GPU clock speed of 723 MHz, and 4096 MB of GDDR5 memory set to run at 1250 MHz through a 256-bit bus. It also features 2048 SPUs, 128 Texture Address Units, and 32 ROPs.

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 in theory be a lot better than the Radeon R9 M390X in general. (explain)

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

Texel Rate

The Radeon HD 6990 should be quite a bit (more or less 72%) more effective at anisotropic filtering than the Radeon R9 M390X. (explain)

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

Pixel Rate

The Radeon HD 6990 is a lot (approximately 130%) better at FSAA than the Radeon R9 M390X, and will be able to handle higher screen resolutions more effectively. (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 maximum amount of information (measured in megabytes per second) that can be moved across the external memory interface in one second. It is calculated by multiplying the card's bus width by its memory speed. If the card has DDR RAM, it must be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The higher the bandwidth is, the faster 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 applied in one second. This is calculated by multiplying the total number of texture units by the core clock speed of the chip. The better the texel rate, the better the card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels in a second.

Pixel Rate: Pixel rate is the maximum amount of pixels the video card could possibly record to its local memory in one second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the amount of ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel rate also depends on quite a few other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to get to the max fill rate.