Geforce GTX 690 vs Radeon HD 3870 X2 512MB

Intro

Compare those specifications to the Radeon HD 3870 X2 512MB, which has a GPU core clock speed of 825 MHz, and 512 MB of GDDR3 memory set to run at 900 MHz through a 256-bit bus. It also is comprised of 320(64x5) SPUs, 16 Texture Address Units, and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Memory Bandwidth

In theory, the Geforce GTX 690 should be 234% quicker than the Radeon HD 3870 X2 512MB in general, because of its higher data rate. (explain)

Geforce GTX 690		384512 MB/sec
Radeon HD 3870 X2 512MB		115200 MB/sec
	Difference: 269312 (234%)

Texel Rate

The Geforce GTX 690 should be a lot (approximately 787%) better at texture filtering than the Radeon HD 3870 X2 512MB. (explain)

Geforce GTX 690		234240 Mtexels/sec
Radeon HD 3870 X2 512MB		26400 Mtexels/sec
	Difference: 207840 (787%)

Pixel Rate

The Geforce GTX 690 is quite a bit (approximately 122%) more effective at full screen anti-aliasing than the Radeon HD 3870 X2 512MB, and will be capable of handling higher screen resolutions better. (explain)

Geforce GTX 690		58560 Mpixels/sec
Radeon HD 3870 X2 512MB		26400 Mpixels/sec
	Difference: 32160 (122%)

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 largest amount of data (in units of megabytes per second) that can be transferred over the external memory interface in one second. It is calculated by multiplying the interface width by its memory speed. If it uses DDR type memory, it should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The better the 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 number of texture map elements (texels) that can be applied per second. This is worked out by multiplying the total texture units by the core speed of the chip. The better this number, the better the video card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied per second.

Pixel Rate: Pixel rate is the maximum number of pixels the video 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 number of Render Output Units by the the core 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 also depends 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.