GeForce GTX 660 vs Radeon R9 M390X

Intro

Compare all that to the Radeon R9 M390X, which uses a 28 nm design. AMD has set the core frequency at 723 MHz. The GDDR5 RAM works at a speed of 1250 MHz on this particular card. It features 2048 SPUs as well as 128 Texture Address Units and 32 Rasterization Operator Units.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon R9 M390X		125 Watts
GeForce GTX 660		140 Watts
	Difference: 15 Watts (12%)

Memory Bandwidth

The Radeon R9 M390X, in theory, should be a bit faster than the GeForce GTX 660 overall. (explain)

Radeon R9 M390X		160000 MB/sec
GeForce GTX 660		144192 MB/sec
	Difference: 15808 (11%)

Texel Rate

The Radeon R9 M390X will be a little bit (about 18%) more effective at AF than the GeForce GTX 660. (explain)

Radeon R9 M390X		92544 Mtexels/sec
GeForce GTX 660		78400 Mtexels/sec
	Difference: 14144 (18%)

Pixel Rate

The GeForce GTX 660 will be a little bit (about 2%) better at FSAA than the Radeon R9 M390X, and should be capable of handling higher resolutions without slowing down too much. (explain)

GeForce GTX 660		23520 Mpixels/sec
Radeon R9 M390X		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 largest amount of information (counted in MB per second) that can be transferred across the external memory interface in one second. It is worked out by multiplying the interface width by its memory speed. In the case of DDR type memory, it should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The higher the bandwidth is, 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 texture map elements (texels) that can be applied in one second. This figure is calculated by multiplying the total amount of texture units by the core clock speed of the chip. The higher the texel rate, the better the card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels in one second.

Pixel Rate: Pixel rate is the most pixels that the graphics chip could possibly record to the local memory per second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the number of Raster Operations Pipelines by the the core speed of the card. 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, especially the memory bandwidth - the lower the memory bandwidth is, the lower the ability to get to the maximum fill rate.