Radeon HD 3870 X2 512MB vs Radeon R7 240

Intro

Compare that to the Radeon R7 240, which comes with a core clock speed of 730 MHz and a DDR3 memory frequency of 900 MHz. It also features a 128-bit bus, and uses a 28 nm design. It is made up of 320 SPUs, 20 TAUs, and 8 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Memory Bandwidth

Theoretically, the Radeon HD 3870 X2 512MB should perform quite a bit faster than the Radeon R7 240 overall. (explain)

Radeon HD 3870 X2 512MB		115200 MB/sec
Radeon R7 240		28800 MB/sec
	Difference: 86400 (300%)

Texel Rate

The Radeon HD 3870 X2 512MB will be much (about 81%) better at texture filtering than the Radeon R7 240. (explain)

Radeon HD 3870 X2 512MB		26400 Mtexels/sec
Radeon R7 240		14600 Mtexels/sec
	Difference: 11800 (81%)

Pixel Rate

The Radeon HD 3870 X2 512MB is a lot (about 352%) better at FSAA than the Radeon R7 240, and also will be capable of handling higher screen resolutions without slowing down too much. (explain)

Radeon HD 3870 X2 512MB		26400 Mpixels/sec
Radeon R7 240		5840 Mpixels/sec
	Difference: 20560 (352%)

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 maximum amount of data (in units of MB per second) that can be moved past the external memory interface in one second. It is worked out by multiplying the interface width by its memory clock speed. If it uses DDR memory, it should be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The higher the memory bandwidth, the faster the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and high resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that are processed per second. This figure is calculated by multiplying the total amount of texture units by the core clock 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 in a second.

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics chip can possibly write to its 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 clock speed. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel fill rate is also dependant 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.