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

Intro

Compare all of that to the Radeon HD 3870 X2 512MB, which has a clock speed of 825 MHz and a GDDR3 memory speed of 900 MHz. It also uses a 256-bit memory bus, and uses a 55 nm design. It is made up of 320(64x5) SPUs, 16 TAUs, and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Memory Bandwidth

Theoretically speaking, the Radeon HD 3870 X2 512MB is 60% faster than the Radeon HD 3870 1GB overall, due to its higher bandwidth. (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 will be a lot (more or less 113%) faster with regards to anisotropic filtering 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

The Radeon HD 3870 X2 512MB should be quite a bit (more or less 113%) more effective at anti-aliasing than the Radeon HD 3870 1GB, and also able to handle higher resolutions while still performing well. (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: Bandwidth is the max amount of information (in units of MB per second) that can be moved across the external memory interface within a second. The number is calculated by multiplying the bus width by the speed of its memory. If it uses DDR type RAM, it should be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The higher the bandwidth is, the better 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 are applied per second. This is calculated by multiplying the total number of texture units by the core 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 a second.

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