Radeon HD 7990 vs Radeon R9 M295X

Intro

Compare all of that to the Radeon R9 M295X, which comes with a GPU core clock speed of 750 MHz, and 4096 MB of GDDR5 RAM running at 1375 MHz through a 256-bit bus. It also is made up of 2048 SPUs, 128 TAUs, and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon R9 M295X		125 Watts
Radeon HD 7990		375 Watts
	Difference: 250 Watts (200%)

Memory Bandwidth

The Radeon HD 7990, in theory, should be much faster than the Radeon R9 M295X overall. (explain)

Radeon HD 7990		576000 MB/sec
Radeon R9 M295X		176000 MB/sec
	Difference: 400000 (227%)

Texel Rate

The Radeon HD 7990 is quite a bit (more or less 153%) more effective at AF than the Radeon R9 M295X. (explain)

Radeon HD 7990		243200 Mtexels/sec
Radeon R9 M295X		96000 Mtexels/sec
	Difference: 147200 (153%)

Pixel Rate

The Radeon HD 7990 should be quite a bit (about 153%) more effective at anti-aliasing than the Radeon R9 M295X, and also capable of handling higher screen resolutions while still performing well. (explain)

Radeon HD 7990		60800 Mpixels/sec
Radeon R9 M295X		24000 Mpixels/sec
	Difference: 36800 (153%)

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 data (counted in megabytes per second) that can be moved across the external memory interface in one second. The number is calculated by multiplying the bus width by its memory clock speed. If it uses DDR type RAM, it should be multiplied by 2 once again. If DDR5, multiply by 4 instead. The higher the card's 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 per second. This figure is worked out by multiplying the total amount of texture units of the card by the core speed of the chip. The better 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 that the graphics chip could possibly record to the local memory per second - measured in millions of pixels per second. The figure is worked out by multiplying the number of ROPs 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 rate also depends on lots of other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the potential to reach the maximum fill rate.