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

Intro

Compare that to the Radeon HD 3870 X2 512MB, which uses a 55 nm design. AMD has clocked the core frequency at 825 MHz. The GDDR3 RAM runs at a speed of 900 MHz on this specific card. It features 320(64x5) SPUs as well as 16 Texture Address Units and 16 Rasterization Operator Units.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Memory Bandwidth

Performance-wise, the Radeon HD 3870 X2 512MB should theoretically be quite a bit superior to the Radeon HD 3870 1GB overall. (explain)

Radeon HD 3870 X2 512MB		115200 MB/sec
Radeon HD 3870 1GB		72000 MB/sec
	Difference: 43200 (60%)

Texel Rate

The Radeon HD 3870 X2 512MB should be quite a bit (approximately 113%) more effective at AF than the Radeon HD 3870 1GB. (explain)

Radeon HD 3870 X2 512MB		26400 Mtexels/sec
Radeon HD 3870 1GB		12400 Mtexels/sec
	Difference: 14000 (113%)

Pixel Rate

If running with lots of anti-aliasing is important to you, then the Radeon HD 3870 X2 512MB is a better choice, by a large margin. (explain)

Radeon HD 3870 X2 512MB		26400 Mpixels/sec
Radeon HD 3870 1GB		12400 Mpixels/sec
	Difference: 14000 (113%)

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 maximum amount of information (measured in MB per second) that can be moved across the external memory interface in one second. The number is worked out by multiplying the card's interface width by its memory clock speed. In the case of DDR RAM, it must be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The higher the bandwidth is, the faster the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and higher screen resolutions.

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

Pixel Rate: Pixel rate is the maximum amount of pixels the graphics card can possibly record to the local memory in one second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the number of ROPs by the the core clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel fill rate is also dependant on quite a few other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the potential to reach the max fill rate.