GeForce GTX 470 vs Radeon HD 3870 X2 1GB

Intro

Compare all that to the Radeon HD 3870 X2 1GB, which uses a 55 nm design. ATi has clocked the core speed at 825 MHz. The GDDR4 RAM runs at a speed of 1126 MHz on this particular model. It features 320(64x5) SPUs as well as 16 Texture Address Units and 16 Rasterization Operator Units.

(No game benchmarks for this combination yet.)

Power Usage and Theoretical Benchmarks

Memory Bandwidth

Theoretically, the Radeon HD 3870 X2 1GB should be just a bit faster than the GeForce GTX 470 overall. (explain)

Radeon HD 3870 X2 1GB		144128 MB/sec
GeForce GTX 470		133920 MB/sec
	Difference: 10208 (8%)

Texel Rate

The GeForce GTX 470 should be quite a bit (more or less 29%) better at texture filtering than the Radeon HD 3870 X2 1GB. (explain)

GeForce GTX 470		33992 Mtexels/sec
Radeon HD 3870 X2 1GB		26400 Mtexels/sec
	Difference: 7592 (29%)

Pixel Rate

If using high levels of AA is important to you, then the Radeon HD 3870 X2 1GB is superior to the GeForce GTX 470, though not by far. (explain)

Radeon HD 3870 X2 1GB		26400 Mpixels/sec
GeForce GTX 470		24280 Mpixels/sec
	Difference: 2120 (9%)

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 (measured in megabytes per second) that can be transported past the external memory interface in one second. It is worked out by multiplying the bus width by its memory clock speed. If the card has DDR type RAM, it must be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The better the bandwidth is, the better the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and high resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that are applied per second. This figure is worked out by multiplying the total number of texture units of the card by the core speed of the chip. The higher this number, the better the video card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels 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 number is calculated by multiplying the number of Raster Operations Pipelines by the the core clock speed. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel fill rate also depends on lots of other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to reach the maximum fill rate.