Radeon HD 6990 vs Radeon R9 M395X

Intro

Compare those specifications to the Radeon R9 M395X, which has a core clock frequency of 723 MHz and a GDDR5 memory speed of 1250 MHz. It also features a 256-bit bus, and uses a 28 nm design. It 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 M395X		125 Watts
Radeon HD 6990		375 Watts
	Difference: 250 Watts (200%)

Memory Bandwidth

Performance-wise, the Radeon HD 6990 should in theory be much superior to the Radeon R9 M395X in general. (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%) faster with regards to AF than the Radeon R9 M395X. (explain)

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

Pixel Rate

The Radeon HD 6990 will be much (approximately 130%) better at full screen anti-aliasing than the Radeon R9 M395X, and also able to handle higher resolutions while still performing well. (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 max amount of information (counted in MB per second) that can be transported across the external memory interface within a second. It's calculated by multiplying the card's bus width by the speed of its memory. If the card has DDR RAM, it should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The better the card's memory bandwidth, 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 amount of texture map elements (texels) that are applied in one second. This number is calculated by multiplying the total number of texture units of the card 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 one second.

Pixel Rate: Pixel rate is the maximum amount of pixels the graphics card can possibly record to its local memory in a second - measured in millions of pixels per second. The number is calculated by multiplying the number of Render Output Units by the the core clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel fill rate also depends on quite a few other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the ability to get to the max fill rate.