Radeon HD 6990 vs Radeon R9 M385X

Intro

Compare those specifications to the Radeon R9 M385X, which features GPU core speed of 1100 MHz, and 4096 MB of GDDR5 RAM set to run at 1500 MHz through a 128-bit bus. It also is made up of 896 Stream Processors, 56 Texture Address Units, and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Memory Bandwidth

In theory, the Radeon HD 6990 should perform much faster than the Radeon R9 M385X overall. (explain)

Radeon HD 6990		320000 MB/sec
Radeon R9 M385X		96000 MB/sec
	Difference: 224000 (233%)

Texel Rate

The Radeon HD 6990 should be much (about 159%) better at anisotropic filtering than the Radeon R9 M385X. (explain)

Radeon HD 6990		159360 Mtexels/sec
Radeon R9 M385X		61600 Mtexels/sec
	Difference: 97760 (159%)

Pixel Rate

If using a high screen resolution is important to you, then the Radeon HD 6990 is a better choice, and very much so. (explain)

Radeon HD 6990		53120 Mpixels/sec
Radeon R9 M385X		17600 Mpixels/sec
	Difference: 35520 (202%)

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 data (in units of MB per second) that can be moved across the external memory interface in one second. It's calculated by multiplying the card's interface width by the speed of its memory. If the card has DDR memory, the result should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The better the memory bandwidth, the better the card will be in general. It especially helps with AA, High Dynamic Range and high resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are processed in one second. This figure is worked out by multiplying the total texture units of the card by the core clock speed of the chip. The higher this number, the better the card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in a second.

Pixel Rate: Pixel rate is the maximum number of pixels the video card could possibly write to its local memory per second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the amount of Render Output Units by the the card's clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel fill rate also depends on lots of other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the ability to get to the maximum fill rate.