Geforce GTX 680 vs Radeon R9 M390X

Intro

Compare those specifications to the Radeon R9 M390X, which has core clock speeds of 723 MHz on the GPU, and 1250 MHz on the 4096 MB of GDDR5 memory. It features 2048 SPUs along with 128 TAUs and 32 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon R9 M390X		125 Watts
Geforce GTX 680		195 Watts
	Difference: 70 Watts (56%)

Memory Bandwidth

As far as performance goes, the Geforce GTX 680 should in theory be a little bit superior to the Radeon R9 M390X overall. (explain)

Geforce GTX 680		192256 MB/sec
Radeon R9 M390X		160000 MB/sec
	Difference: 32256 (20%)

Texel Rate

The Geforce GTX 680 is a lot (about 39%) faster with regards to texture filtering than the Radeon R9 M390X. (explain)

Geforce GTX 680		128768 Mtexels/sec
Radeon R9 M390X		92544 Mtexels/sec
	Difference: 36224 (39%)

Pixel Rate

The Geforce GTX 680 is quite a bit (approximately 39%) more effective at anti-aliasing than the Radeon R9 M390X, and also able to handle higher resolutions without losing too much performance. (explain)

Geforce GTX 680		32192 Mpixels/sec
Radeon R9 M390X		23136 Mpixels/sec
	Difference: 9056 (39%)

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 maximum amount of data (measured in megabytes per second) that can be transported over the external memory interface within a second. The number is worked out by multiplying the interface width by the speed of its memory. If the card has DDR RAM, the result should be multiplied by 2 again. If DDR5, multiply by 4 instead. The higher the memory bandwidth, the better the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and high resolutions.

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

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics chip could possibly record to the local memory in one second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the number of Render Output Units by the clock speed of the card. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel rate is also dependant on lots of other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to reach the max fill rate.