GeForce GTX 870M vs Radeon R9 M380

Intro

Compare those specs to the Radeon R9 M380, which has GPU core speed of 1000 MHz, and 4096 MB of GDDR5 memory set to run at 1500 MHz through a 128-bit bus. It also is made up of 640 Stream Processors, 40 Texture Address Units, and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Memory Bandwidth

Both cards have the exact same bandwidth, so theoretically they should perform exactly the same. (explain)

Texel Rate

The GeForce GTX 870M should be much (about 163%) faster with regards to texture filtering than the Radeon R9 M380. (explain)

GeForce GTX 870M		105392 Mtexels/sec
Radeon R9 M380		40000 Mtexels/sec
	Difference: 65392 (163%)

Pixel Rate

The GeForce GTX 870M is a lot (about 41%) better at AA than the Radeon R9 M380, and will be able to handle higher screen resolutions without losing too much performance. (explain)

GeForce GTX 870M		22584 Mpixels/sec
Radeon R9 M380		16000 Mpixels/sec
	Difference: 6584 (41%)

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 largest amount of information (measured in MB per second) that can be transferred past 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 RAM, it should be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The higher the bandwidth is, the faster the card will be in general. It especially helps with AA, High Dynamic Range and high resolutions.

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

Pixel Rate: Pixel rate is the most pixels that the graphics card could possibly write to its local memory per second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the amount of Render Output Units by the the core speed of the card. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel rate is also dependant on quite a few other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the ability to get to the max fill rate.