GeForce GTX 870M vs Radeon R9 M390X

Intro

Compare those specifications to the Radeon R9 M390X, which makes use of a 28 nm design. AMD has set the core frequency at 723 MHz. The GDDR5 memory is set to run at a frequency of 1250 MHz on this particular model. It features 2048 SPUs as well as 128 TAUs and 32 Rasterization Operator Units.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GTX 870M		110 Watts
Radeon R9 M390X		125 Watts
	Difference: 15 Watts (14%)

Memory Bandwidth

Theoretically speaking, the Radeon R9 M390X will be 67% quicker than the GeForce GTX 870M in general, due to its greater data rate. (explain)

Radeon R9 M390X		160000 MB/sec
GeForce GTX 870M		96000 MB/sec
	Difference: 64000 (67%)

Texel Rate

The GeForce GTX 870M will be a little bit (more or less 14%) faster with regards to texture filtering than the Radeon R9 M390X. (explain)

GeForce GTX 870M		105392 Mtexels/sec
Radeon R9 M390X		92544 Mtexels/sec
	Difference: 12848 (14%)

Pixel Rate

If using lots of anti-aliasing is important to you, then the Radeon R9 M390X is a better choice, though not by far. (explain)

Radeon R9 M390X		23136 Mpixels/sec
GeForce GTX 870M		22584 Mpixels/sec
	Difference: 552 (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: Memory bandwidth is the max amount of information (counted in MB per second) that can be transferred across the external memory interface in a second. The number is calculated by multiplying the interface width by its memory speed. If it uses DDR type memory, it must be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The better the card's 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 are 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 higher the texel rate, the better the card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied per second.

Pixel Rate: Pixel rate is the maximum number of pixels that the graphics card could possibly write to its local memory in a second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the number of ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel rate is also dependant on many other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the ability to get to the maximum fill rate.