GeForce GTX 660 vs Radeon HD 3870 X2 1GB

Intro

Compare those specifications to the Radeon HD 3870 X2 1GB, which has core speeds of 825 MHz on the GPU, and 1126 MHz on the 1024 MB of GDDR4 RAM. It features 320(64x5) SPUs along with 16 Texture Address Units and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Memory Bandwidth

The GeForce GTX 660, in theory, should be a bit faster than the Radeon HD 3870 X2 1GB in general. (explain)

GeForce GTX 660		144192 MB/sec
Radeon HD 3870 X2 1GB		144128 MB/sec
	Difference: 64 (0%)

Texel Rate

The GeForce GTX 660 should be much (more or less 197%) faster with regards to anisotropic filtering than the Radeon HD 3870 X2 1GB. (explain)

GeForce GTX 660		78400 Mtexels/sec
Radeon HD 3870 X2 1GB		26400 Mtexels/sec
	Difference: 52000 (197%)

Pixel Rate

If using high levels of AA is important to you, then the Radeon HD 3870 X2 1GB is a better choice, but only just. (explain)

Radeon HD 3870 X2 1GB		26400 Mpixels/sec
GeForce GTX 660		23520 Mpixels/sec
	Difference: 2880 (12%)

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 largest amount of information (measured in MB per second) that can be moved past the external memory interface in a second. It's calculated by multiplying the bus width by the speed of its memory. In the case of DDR memory, it must be multiplied by 2 again. If DDR5, multiply by 4 instead. 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 texture map elements (texels) that are applied in one second. This figure is worked out by multiplying the total texture units by the core speed of the chip. The higher this number, the better the card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in one second.

Pixel Rate: Pixel rate is the most pixels the video card could possibly record to the local memory per second - measured in millions of pixels per second. The number is calculated by multiplying the number of ROPs by the clock speed of the card. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel output rate is also dependant on lots of other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the ability to get to the max fill rate.