Radeon HD 7950 3GB vs Radeon R9 M275X

Intro

Compare all of that to the Radeon R9 M275X, which uses a 28 nm design. AMD has set the core frequency at 900 MHz. The GDDR5 memory is set to run at a speed of 1125 MHz on this model. It features 640 SPUs along with 40 Texture Address Units and 16 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon R9 M275X		50 Watts
Radeon HD 7950 3GB		200 Watts
	Difference: 150 Watts (300%)

Memory Bandwidth

Theoretically speaking, the Radeon HD 7950 3GB is 233% quicker than the Radeon R9 M275X in general, due to its greater data rate. (explain)

Radeon HD 7950 3GB		240000 MB/sec
Radeon R9 M275X		72000 MB/sec
	Difference: 168000 (233%)

Texel Rate

The Radeon HD 7950 3GB should be quite a bit (approximately 149%) better at AF than the Radeon R9 M275X. (explain)

Radeon HD 7950 3GB		89600 Mtexels/sec
Radeon R9 M275X		36000 Mtexels/sec
	Difference: 53600 (149%)

Pixel Rate

The Radeon HD 7950 3GB will be much (approximately 78%) more effective at full screen anti-aliasing than the Radeon R9 M275X, and will be able to handle higher screen resolutions more effectively. (explain)

Radeon HD 7950 3GB		25600 Mpixels/sec
Radeon R9 M275X		14400 Mpixels/sec
	Difference: 11200 (78%)

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.

Price Comparison

Specifications

Memory Bandwidth: Bandwidth is the max amount of information (counted in megabytes per second) that can be transferred past the external memory interface in one second. It's calculated by multiplying the interface width by the speed of its memory. If the card has DDR type memory, it must be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The higher 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 texture map elements (texels) that are applied per second. This is calculated by multiplying the total texture units of the card by the core 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 applied in one second.

Pixel Rate: Pixel rate is the most pixels that the graphics card could possibly write to the local memory in one second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the number of colour 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 fill rate also depends on lots of other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to get to the maximum fill rate.