Radeon HD 3870 X2 1GB vs Radeon HD 5750 512MB

Intro

Compare that to the Radeon HD 5750 512MB, which comes with a clock frequency of 700 MHz and a GDDR5 memory frequency of 1150 MHz. It also makes use of a 128-bit memory bus, and uses a 40 nm design. It is made up of 720(144x5) SPUs, 36 Texture Address Units, and 16 ROPs.

(No game benchmarks for this combination yet.)

Power Usage and Theoretical Benchmarks

Memory Bandwidth

The Radeon HD 3870 X2 1GB, in theory, should perform much faster than the Radeon HD 5750 512MB overall. (explain)

Radeon HD 3870 X2 1GB		144128 MB/sec
Radeon HD 5750 512MB		73600 MB/sec
	Difference: 70528 (96%)

Texel Rate

The Radeon HD 3870 X2 1GB is a little bit (about 5%) faster with regards to texture filtering than the Radeon HD 5750 512MB. (explain)

Radeon HD 3870 X2 1GB		26400 Mtexels/sec
Radeon HD 5750 512MB		25200 Mtexels/sec
	Difference: 1200 (5%)

Pixel Rate

The Radeon HD 3870 X2 1GB should be quite a bit (about 136%) more effective at full screen anti-aliasing than the Radeon HD 5750 512MB, and capable of handling higher screen resolutions without slowing down too much. (explain)

Radeon HD 3870 X2 1GB		26400 Mpixels/sec
Radeon HD 5750 512MB		11200 Mpixels/sec
	Difference: 15200 (136%)

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 max amount of information (in units of MB per second) that can be transferred over the external memory interface in a second. The number is calculated by multiplying the interface width by its memory speed. In the case of DDR RAM, it must be multiplied by 2 once again. If 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 high resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that are applied in one second. This number is calculated by multiplying the total number of texture units of the card by the core clock speed of the chip. The higher the texel rate, the better the card will be at handling 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 can possibly write to its local memory per second - measured in millions of pixels per second. The number is calculated by multiplying the number of ROPs by the the core 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 of the card - the lower the memory bandwidth is, the lower the ability to reach the max fill rate.