Radeon HD 3870 X2 512MB vs Radeon R9 M275X

Intro

Compare all that to the Radeon R9 M275X, which uses a 28 nm design. AMD has clocked the core speed at 900 MHz. The GDDR5 memory works at a frequency of 1125 MHz on this specific card. It features 640 SPUs as well as 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 will be 60% quicker than the Radeon R9 M275X in general, because of its higher data rate. (explain)

Radeon HD 3870 X2 512MB		115200 MB/sec
Radeon R9 M275X		72000 MB/sec
	Difference: 43200 (60%)

Texel Rate

The Radeon R9 M275X will be a lot (more or less 36%) better at AF than the Radeon HD 3870 X2 512MB. (explain)

Radeon R9 M275X		36000 Mtexels/sec
Radeon HD 3870 X2 512MB		26400 Mtexels/sec
	Difference: 9600 (36%)

Pixel Rate

The Radeon HD 3870 X2 512MB is much (approximately 83%) better at anti-aliasing than the Radeon R9 M275X, and will be capable of handling higher resolutions while still performing well. (explain)

Radeon HD 3870 X2 512MB		26400 Mpixels/sec
Radeon R9 M275X		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: Memory bandwidth is the largest amount of data (measured in MB per second) that can be transferred past the external memory interface in a second. It's worked out by multiplying the bus width by its memory clock speed. If it uses DDR type memory, it should be multiplied by 2 once again. If DDR5, multiply by 4 instead. The better the memory bandwidth, the faster the card will be in general. It especially helps with AA, High Dynamic Range and higher screen resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that can be processed per second. This figure is calculated by multiplying the total amount of texture units of the card by the core clock speed of the chip. The higher the texel rate, the better the video card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels per second.

Pixel Rate: Pixel rate is the most pixels that the graphics card could possibly record to the local memory in one second - measured in millions of pixels per second. The figure is calculated by multiplying the amount of Render Output Units by the clock speed of the card. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel fill rate is also dependant on many other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to get to the maximum fill rate.