GeForce GTX 870M vs Radeon HD 3870 X2 512MB

Intro

Compare those specifications to the Radeon HD 3870 X2 512MB, which comes with clock speeds of 825 MHz on the GPU, and 900 MHz on the 512 MB of GDDR3 memory. It features 320(64x5) SPUs as well as 16 Texture Address Units and 16 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Memory Bandwidth

As far as performance goes, the Radeon HD 3870 X2 512MB should in theory be a small bit better 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 will be a lot (about 299%) more effective 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

The Radeon HD 3870 X2 512MB should be a bit (more or less 17%) faster with regards to AA than the GeForce GTX 870M, and able to handle higher resolutions better. (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: Memory bandwidth is the maximum amount of data (counted in MB per second) that can be transported over the external memory interface in a second. It's calculated by multiplying the card's interface width by its memory speed. If it uses DDR type memory, it must be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The better the bandwidth is, the faster the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.

Texel Rate: Texel rate is the maximum 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 graphics card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in a second.

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics card could possibly write to its local memory per second - measured in millions of pixels per second. The figure is worked out by multiplying the amount of colour ROPs by the the core speed of the card. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel fill 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 reach the max fill rate.