GeForce GTX 660 vs Radeon R9 M395X

Intro

Compare that to the Radeon R9 M395X, which comes with GPU core speed of 723 MHz, and 4096 MB of GDDR5 memory set to run at 1250 MHz through a 256-bit bus. It also features 2048 Stream Processors, 128 TAUs, and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon R9 M395X		125 Watts
GeForce GTX 660		140 Watts
	Difference: 15 Watts (12%)

Memory Bandwidth

Performance-wise, the Radeon R9 M395X should theoretically be a small bit superior to the GeForce GTX 660 overall. (explain)

Radeon R9 M395X		160000 MB/sec
GeForce GTX 660		144192 MB/sec
	Difference: 15808 (11%)

Texel Rate

The Radeon R9 M395X should be just a bit (about 18%) better at texture filtering than the GeForce GTX 660. (explain)

Radeon R9 M395X		92544 Mtexels/sec
GeForce GTX 660		78400 Mtexels/sec
	Difference: 14144 (18%)

Pixel Rate

The GeForce GTX 660 is a little bit (approximately 2%) faster with regards to FSAA than the Radeon R9 M395X, and should be capable of handling higher resolutions better. (explain)

GeForce GTX 660		23520 Mpixels/sec
Radeon R9 M395X		23136 Mpixels/sec
	Difference: 384 (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: Bandwidth is the max amount of data (in units of MB per second) that can be transferred over the external memory interface in one second. It is calculated by multiplying the bus width by its memory speed. If the card has DDR type memory, it must be multiplied by 2 again. If DDR5, multiply by 4 instead. The higher the card's memory bandwidth, the faster 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 can be processed in one second. This is calculated by multiplying the total number of texture units by the core clock speed of the chip. The higher this number, the better the graphics card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels in a second.

Pixel Rate: Pixel rate is the most pixels that the graphics card could possibly write to the local memory in a second - measured in millions of pixels per second. The figure is worked out by multiplying the number of colour ROPs by the the core speed of the card. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel fill rate also depends on many other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to reach the maximum fill rate.