Radeon HD 3870 X2 512MB vs Radeon R9 M265X

Intro

Compare those specifications to the Radeon R9 M265X, which uses a 28 nm design. AMD has set the core frequency at 575 MHz. The GDDR5 RAM is set to run at a frequency of 1125 MHz on this specific card. It features 640 SPUs along with 40 Texture Address Units and 16 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Memory Bandwidth

In theory, the Radeon HD 3870 X2 512MB should be 60% quicker than the Radeon R9 M265X in general, because of its higher data rate. (explain)

Radeon HD 3870 X2 512MB		115200 MB/sec
Radeon R9 M265X		72000 MB/sec
	Difference: 43200 (60%)

Texel Rate

The Radeon HD 3870 X2 512MB will be a bit (about 15%) better at AF than the Radeon R9 M265X. (explain)

Radeon HD 3870 X2 512MB		26400 Mtexels/sec
Radeon R9 M265X		23000 Mtexels/sec
	Difference: 3400 (15%)

Pixel Rate

If using high levels of AA is important to you, then the Radeon HD 3870 X2 512MB is a better choice, and very much so. (explain)

Radeon HD 3870 X2 512MB		26400 Mpixels/sec
Radeon R9 M265X		9200 Mpixels/sec
	Difference: 17200 (187%)

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 information (measured in MB per second) that can be transferred over the external memory interface in one second. The number is calculated by multiplying the card's interface width by its memory speed. In the case of DDR type memory, it must be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The higher the bandwidth is, 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 texture map elements (texels) that can be processed in one second. This is calculated 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 graphics card will be at handling 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 video card can possibly write to the local memory in one second - measured in millions of pixels per second. The number is calculated by multiplying the amount of Render Output Units by the the card's 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 rate also depends on lots of other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the potential to get to the maximum fill rate.