GeForce GTX 650 vs Radeon HD 3870 X2 512MB

Intro

Compare those specs to the Radeon HD 3870 X2 512MB, which features a core clock speed of 825 MHz and a GDDR3 memory frequency of 900 MHz. It also features a 256-bit memory bus, and uses a 55 nm design. It is comprised of 320(64x5) SPUs, 16 Texture Address Units, and 16 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Memory Bandwidth

In theory, the Radeon HD 3870 X2 512MB is 44% quicker than the GeForce GTX 650 in general, due to its higher bandwidth. (explain)

Radeon HD 3870 X2 512MB		115200 MB/sec
GeForce GTX 650		80000 MB/sec
	Difference: 35200 (44%)

Texel Rate

The GeForce GTX 650 should be a lot (about 28%) faster with regards to anisotropic filtering than the Radeon HD 3870 X2 512MB. (explain)

GeForce GTX 650		33856 Mtexels/sec
Radeon HD 3870 X2 512MB		26400 Mtexels/sec
	Difference: 7456 (28%)

Pixel Rate

The Radeon HD 3870 X2 512MB is much (more or less 56%) better at anti-aliasing than the GeForce GTX 650, and will be able to handle higher screen resolutions without slowing down too much. (explain)

Radeon HD 3870 X2 512MB		26400 Mpixels/sec
GeForce GTX 650		16928 Mpixels/sec
	Difference: 9472 (56%)

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 maximum amount of information (counted in megabytes per second) that can be moved over the external memory interface in one second. It is worked out by multiplying the card's interface width by its memory clock speed. If it uses DDR type RAM, it must be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The better the card's memory bandwidth, the faster the card will be in general. It especially helps with AA, HDR and higher screen resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that can be processed per second. This figure is calculated by multiplying the total amount of texture units by the core speed of the chip. The better the texel rate, the better the card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels per second.

Pixel Rate: Pixel rate is the maximum amount 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 Render Output Units by the the card's clock speed. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel rate is also dependant on lots of other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to get to the maximum fill rate.