Radeon HD 3870 512MB vs Radeon HD 4850 X2 1GB

Intro

Compare those specifications to the Radeon HD 4850 X2 1GB, which uses a 55 nm design. AMD has set the core speed at 625 MHz. The GDDR3 RAM runs at a speed of 993 MHz on this card. It features 800(160x5) SPUs as well as 40 Texture Address Units and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 3870 512MB		106 Watts
Radeon HD 4850 X2 1GB		250 Watts
	Difference: 144 Watts (136%)

Memory Bandwidth

The Radeon HD 4850 X2 1GB, in theory, should perform a lot faster than the Radeon HD 3870 512MB in general. (explain)

Radeon HD 4850 X2 1GB		127104 MB/sec
Radeon HD 3870 512MB		57600 MB/sec
	Difference: 69504 (121%)

Texel Rate

The Radeon HD 4850 X2 1GB should be quite a bit (more or less 303%) more effective at texture filtering than the Radeon HD 3870 512MB. (explain)

Radeon HD 4850 X2 1GB		50000 Mtexels/sec
Radeon HD 3870 512MB		12400 Mtexels/sec
	Difference: 37600 (303%)

Pixel Rate

The Radeon HD 4850 X2 1GB should be quite a bit (about 61%) better at AA than the Radeon HD 3870 512MB, and also should be capable of handling higher resolutions better. (explain)

Radeon HD 4850 X2 1GB		20000 Mpixels/sec
Radeon HD 3870 512MB		12400 Mpixels/sec
	Difference: 7600 (61%)

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 information (counted in megabytes per second) that can be transported over the external memory interface in a second. It is calculated by multiplying the card's interface width by its memory clock speed. If it uses DDR type RAM, it should be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The higher the bandwidth is, the faster the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that can be processed in one second. This figure is calculated by multiplying the total amount of texture units by the core speed of the chip. The better the texel rate, the better the graphics card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels per second.

Pixel Rate: Pixel rate is the most pixels that the graphics chip can possibly write to the local memory per second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the amount of Render Output Units by the the core speed of the card. ROPs (Raster Operations Pipelines - aka 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, especially the memory bandwidth - the lower the bandwidth is, the lower the potential to reach the maximum fill rate.