GeForce GTX 850M vs Radeon R9 M390X

Intro

Compare those specs to the Radeon R9 M390X, which has GPU clock speed of 723 MHz, and 4096 MB of GDDR5 RAM running at 1250 MHz through a 256-bit bus. It also is made up of 2048 SPUs, 128 TAUs, and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GTX 850M		40 Watts
Radeon R9 M390X		125 Watts
	Difference: 85 Watts (213%)

Memory Bandwidth

In theory, the Radeon R9 M390X should be 400% quicker than the GeForce GTX 850M in general, due to its greater data rate. (explain)

Radeon R9 M390X		160000 MB/sec
GeForce GTX 850M		32000 MB/sec
	Difference: 128000 (400%)

Texel Rate

The Radeon R9 M390X will be much (approximately 164%) better at texture filtering than the GeForce GTX 850M. (explain)

Radeon R9 M390X		92544 Mtexels/sec
GeForce GTX 850M		35040 Mtexels/sec
	Difference: 57504 (164%)

Pixel Rate

If using high levels of AA is important to you, then the Radeon R9 M390X is a better choice, by far. (explain)

Radeon R9 M390X		23136 Mpixels/sec
GeForce GTX 850M		14016 Mpixels/sec
	Difference: 9120 (65%)

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 data (in units of 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 its memory clock speed. In the case of DDR type memory, it must 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 higher screen resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are applied in one second. This is worked out by multiplying the total number of texture units by the core clock speed of the chip. The better the texel rate, the better the graphics card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in one second.

Pixel Rate: Pixel rate is the maximum amount of pixels the graphics card could possibly write to its local memory in one second - measured in millions of pixels per second. The figure is worked out by multiplying the number of Render Output Units by the the card's clock speed. 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 is also dependant on many other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to get to the maximum fill rate.