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

Intro

Compare those specs to the Radeon HD 5750 1GB, which comes with a GPU core clock speed of 700 MHz, and 1024 MB of GDDR5 memory set to run at 1150 MHz through a 128-bit bus. It also is made up of 720(144x5) SPUs, 36 Texture Address Units, and 16 Raster Operation Units.

(No game benchmarks for this combination yet.)

Power Usage and Theoretical Benchmarks

Memory Bandwidth

Theoretically speaking, the Radeon HD 3870 X2 1GB is 96% quicker than the Radeon HD 5750 1GB in general, due to its greater bandwidth. (explain)

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

Texel Rate

The Radeon HD 3870 X2 1GB is a little bit (approximately 5%) better at AF than the Radeon HD 5750 1GB. (explain)

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

Pixel Rate

The Radeon HD 3870 X2 1GB should be a lot (approximately 136%) better at FSAA than the Radeon HD 5750 1GB, and also should be able to handle higher resolutions without losing too much performance. (explain)

Radeon HD 3870 X2 1GB		26400 Mpixels/sec
Radeon HD 5750 1GB		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 data (counted in MB per second) that can be transported past the external memory interface in a second. It's worked out by multiplying the card's interface width by its memory speed. In the case of DDR memory, the result should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The better the card's memory bandwidth, 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 amount of texture map elements (texels) that are applied per second. This figure is calculated by multiplying the total amount of texture units of the card by the core speed of the chip. The higher this number, the better the card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels in one second.

Pixel Rate: Pixel rate is the most pixels that the graphics card can possibly write to the local memory per second - measured in millions of pixels per second. The number is calculated by multiplying the number of colour ROPs by the the core speed of the card. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel rate also depends on quite a few other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to get to the maximum fill rate.