GeForce GTX 980M vs Radeon R9 M390X

Intro

Compare those specs to the Radeon R9 M390X, which has a core clock speed of 723 MHz and a GDDR5 memory frequency of 1250 MHz. It also uses a 256-bit bus, and uses a 28 nm design. It is comprised of 2048 SPUs, 128 TAUs, and 32 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GTX 980M		100 Watts
Radeon R9 M390X		125 Watts
	Difference: 25 Watts (25%)

Memory Bandwidth

In theory, the Radeon R9 M390X will be 25% faster than the GeForce GTX 980M overall, due to its greater bandwidth. (explain)

Radeon R9 M390X		160000 MB/sec
GeForce GTX 980M		128000 MB/sec
	Difference: 32000 (25%)

Texel Rate

The GeForce GTX 980M will be a small bit (more or less 8%) more effective at anisotropic filtering than the Radeon R9 M390X. (explain)

GeForce GTX 980M		99648 Mtexels/sec
Radeon R9 M390X		92544 Mtexels/sec
	Difference: 7104 (8%)

Pixel Rate

The GeForce GTX 980M will be quite a bit (more or less 187%) faster with regards to anti-aliasing than the Radeon R9 M390X, and should be capable of handling higher screen resolutions better. (explain)

GeForce GTX 980M		66432 Mpixels/sec
Radeon R9 M390X		23136 Mpixels/sec
	Difference: 43296 (187%)

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 information (counted in MB per second) that can be transferred past the external memory interface within a second. It is worked out by multiplying the bus width by its memory clock speed. If the card has DDR type RAM, the result should be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The higher the card's memory bandwidth, the faster the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and higher screen resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that are applied in one second. This 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 applied in one second.

Pixel Rate: Pixel rate is the most pixels the video card could possibly record to its local memory per second - measured in millions of pixels per second. The number is calculated by multiplying the amount of Raster Operations Pipelines by the the core speed of the card. ROPs (Raster Operations Pipelines - sometimes also referred to as 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 of the card - the lower the memory bandwidth is, the lower the ability to get to the maximum fill rate.