GeForce GTX 660 Ti vs Radeon R9 M390X

Intro

Compare those specs to the Radeon R9 M390X, which comes with GPU core speed of 723 MHz, and 4096 MB of GDDR5 RAM running at 1250 MHz through a 256-bit bus. It also is comprised of 2048 Stream Processors, 128 Texture Address Units, and 32 ROPs.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon R9 M390X		125 Watts
GeForce GTX 660 Ti		150 Watts
	Difference: 25 Watts (20%)

Memory Bandwidth

Theoretically, the Radeon R9 M390X should be just a bit faster than the GeForce GTX 660 Ti in general. (explain)

Radeon R9 M390X		160000 MB/sec
GeForce GTX 660 Ti		144000 MB/sec
	Difference: 16000 (11%)

Texel Rate

The GeForce GTX 660 Ti is just a bit (more or less 11%) better at AF than the Radeon R9 M390X. (explain)

GeForce GTX 660 Ti		102480 Mtexels/sec
Radeon R9 M390X		92544 Mtexels/sec
	Difference: 9936 (11%)

Pixel Rate

If running with a high screen resolution is important to you, then the Radeon R9 M390X is the winner, though only just barely. (explain)

Radeon R9 M390X		23136 Mpixels/sec
GeForce GTX 660 Ti		21960 Mpixels/sec
	Difference: 1176 (5%)

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 maximum amount of data (measured in megabytes per second) that can be transferred across the external memory interface in a second. It's calculated by multiplying the card's interface width by its memory speed. If it uses DDR RAM, it should 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 anti-aliasing, HDR and high resolutions.

Texel Rate: Texel rate is the maximum 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 processed in one second.

Pixel Rate: Pixel rate is the maximum number of pixels the video card can possibly write to its local memory in one second - measured in millions of pixels per second. The number is worked out by multiplying the amount of Render Output Units by the clock speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel rate also depends on many other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the ability to get to the max fill rate.