GeForce GTX 870M vs Radeon HD 3870 X2 512MB

Intro

Compare all of that to the Radeon HD 3870 X2 512MB, which has a GPU core clock speed of 825 MHz, and 512 MB of GDDR3 RAM running at 900 MHz through a 256-bit bus. It also features 320(64x5) SPUs, 16 Texture Address Units, and 16 Raster Operation Units.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Memory Bandwidth

The Radeon HD 3870 X2 512MB, in theory, should be a little bit faster than the GeForce GTX 870M in general. (explain)

Radeon HD 3870 X2 512MB		115200 MB/sec
GeForce GTX 870M		96000 MB/sec
	Difference: 19200 (20%)

Texel Rate

The GeForce GTX 870M is much (approximately 299%) better at anisotropic filtering than the Radeon HD 3870 X2 512MB. (explain)

GeForce GTX 870M		105392 Mtexels/sec
Radeon HD 3870 X2 512MB		26400 Mtexels/sec
	Difference: 78992 (299%)

Pixel Rate

If using lots of anti-aliasing is important to you, then the Radeon HD 3870 X2 512MB is superior to the GeForce GTX 870M, but not by far. (explain)

Radeon HD 3870 X2 512MB		26400 Mpixels/sec
GeForce GTX 870M		22584 Mpixels/sec
	Difference: 3816 (17%)

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.

One or more cards in this comparison are multi-core. This means that their bandwidth, texel and pixel rates are theoretically doubled - this does not mean the card will actually perform twice as fast, but only that it should in theory be able to. Actual game benchmarks will give a more accurate idea of what it's capable of.

Price Comparison

Specifications

Memory Bandwidth: Bandwidth is the max amount of information (in units of megabytes per second) that can be transported over the external memory interface within a second. It's calculated by multiplying the card's bus width by its memory clock speed. If the card has DDR type memory, it must be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The higher the card's memory bandwidth, the better 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 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 this number, the better the card will be at 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 chip can possibly record to its local memory per second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the number of Render Output Units by the the core clock speed. 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 of the card - the lower the memory bandwidth is, the lower the potential to get to the max fill rate.