Radeon HD 3870 X2 512MB vs Radeon R7 M265

Intro

Compare all of that to the Radeon R7 M265, which comes with a clock speed of 725 MHz and a DDR3 memory speed of 1000 MHz. It also uses a 128-bit bus, and uses a 28 nm design. It is made up of 384 SPUs, 24 Texture Address Units, and 8 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Memory Bandwidth

Theoretically speaking, the Radeon HD 3870 X2 512MB should be 260% faster than the Radeon R7 M265 in general, due to its higher bandwidth. (explain)

Radeon HD 3870 X2 512MB		115200 MB/sec
Radeon R7 M265		32000 MB/sec
	Difference: 83200 (260%)

Texel Rate

The Radeon HD 3870 X2 512MB will be a lot (about 52%) better at anisotropic filtering than the Radeon R7 M265. (explain)

Radeon HD 3870 X2 512MB		26400 Mtexels/sec
Radeon R7 M265		17400 Mtexels/sec
	Difference: 9000 (52%)

Pixel Rate

The Radeon HD 3870 X2 512MB is much (about 355%) better at full screen anti-aliasing than the Radeon R7 M265, and also will be able to handle higher screen resolutions without slowing down too much. (explain)

Radeon HD 3870 X2 512MB		26400 Mpixels/sec
Radeon R7 M265		5800 Mpixels/sec
	Difference: 20600 (355%)

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 max amount of information (measured in megabytes per second) that can be transported across the external memory interface within a second. It's worked out by multiplying the card's bus width by its memory clock speed. If the card has DDR type memory, the result should be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The better the card's memory bandwidth, 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 texture map elements (texels) that can be applied in one second. This number is calculated by multiplying the total amount of texture units of the card by the core clock speed of the chip. The better the texel rate, the better the 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 number of pixels the video card can possibly write to the local memory per second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the amount of ROPs 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 fill rate is also dependant on lots of other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to get to the maximum fill rate.