GeForce GTX 660 vs Radeon R9 M295X

Intro

Compare those specifications to the Radeon R9 M295X, which has core clock speeds of 750 MHz on the GPU, and 1375 MHz on the 4096 MB of GDDR5 RAM. It features 2048 SPUs as well as 128 Texture Address Units and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon R9 M295X		125 Watts
GeForce GTX 660		140 Watts
	Difference: 15 Watts (12%)

Memory Bandwidth

As far as performance goes, the Radeon R9 M295X should theoretically be much superior to the GeForce GTX 660 overall. (explain)

Radeon R9 M295X		176000 MB/sec
GeForce GTX 660		144192 MB/sec
	Difference: 31808 (22%)

Texel Rate

The Radeon R9 M295X will be much (more or less 22%) more effective at AF than the GeForce GTX 660. (explain)

Radeon R9 M295X		96000 Mtexels/sec
GeForce GTX 660		78400 Mtexels/sec
	Difference: 17600 (22%)

Pixel Rate

If running with high levels of AA is important to you, then the Radeon R9 M295X is the winner, though not by far. (explain)

Radeon R9 M295X		24000 Mpixels/sec
GeForce GTX 660		23520 Mpixels/sec
	Difference: 480 (2%)

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: Memory bandwidth is the largest amount of data (measured in MB per second) that can be moved over the external memory interface in a second. It is calculated by multiplying the bus width by its memory clock speed. In the case of DDR memory, it must be multiplied by 2 once again. If DDR5, multiply by 4 instead. The better the card's memory bandwidth, the better the card will be in general. It especially helps with AA, HDR and high resolutions.

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

Pixel Rate: Pixel rate is the maximum amount of pixels the graphics card could possibly record to the local memory in a second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the number of ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel output rate is also dependant on quite a few other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the ability to get to the max fill rate.