Radeon HD 3870 X2 1GB vs Radeon R9 M280X

Intro

Compare that to the Radeon R9 M280X, which comes with a GPU core clock speed of 900 MHz, and 4096 MB of GDDR5 memory set to run at 1375 MHz through a 128-bit bus. It also is made up of 896 SPUs, 56 Texture Address Units, and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Memory Bandwidth

In theory, the Radeon HD 3870 X2 1GB should be quite a bit faster than the Radeon R9 M280X overall. (explain)

Radeon HD 3870 X2 1GB		144128 MB/sec
Radeon R9 M280X		88000 MB/sec
	Difference: 56128 (64%)

Texel Rate

The Radeon R9 M280X will be quite a bit (approximately 91%) better at texture filtering than the Radeon HD 3870 X2 1GB. (explain)

Radeon R9 M280X		50400 Mtexels/sec
Radeon HD 3870 X2 1GB		26400 Mtexels/sec
	Difference: 24000 (91%)

Pixel Rate

The Radeon HD 3870 X2 1GB will be much (more or less 83%) more effective at FSAA than the Radeon R9 M280X, and also should be capable of handling higher screen resolutions better. (explain)

Radeon HD 3870 X2 1GB		26400 Mpixels/sec
Radeon R9 M280X		14400 Mpixels/sec
	Difference: 12000 (83%)

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 data (counted in megabytes per second) that can be moved across the external memory interface within a second. It is calculated by multiplying the interface width by its memory speed. In the case of DDR memory, it should be multiplied by 2 once again. If DDR5, multiply by 4 instead. The higher the card's memory bandwidth, the better the card will be in general. It especially helps with AA, HDR and higher screen resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are applied per second. This number is worked out by multiplying the total amount 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 the video card can possibly record to the local memory per second - measured in millions of pixels per second. The figure is worked out by multiplying the amount of colour ROPs by the the core speed of the card. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel rate also depends on many other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to get to the max fill rate.