Radeon HD 3870 X2 1GB vs Radeon R9 M295X

Intro

Compare all that to the Radeon R9 M295X, which has GPU core speed of 750 MHz, and 4096 MB of GDDR5 RAM running at 1375 MHz through a 256-bit bus. It also features 2048 SPUs, 128 Texture Address Units, and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Memory Bandwidth

As far as performance goes, the Radeon R9 M295X should theoretically be much superior to the Radeon HD 3870 X2 1GB overall. (explain)

Radeon R9 M295X		176000 MB/sec
Radeon HD 3870 X2 1GB		144128 MB/sec
	Difference: 31872 (22%)

Texel Rate

The Radeon R9 M295X will be a lot (more or less 264%) faster with regards to anisotropic filtering than the Radeon HD 3870 X2 1GB. (explain)

Radeon R9 M295X		96000 Mtexels/sec
Radeon HD 3870 X2 1GB		26400 Mtexels/sec
	Difference: 69600 (264%)

Pixel Rate

If using a high screen resolution is important to you, then the Radeon HD 3870 X2 1GB is a better choice, but it probably won't make a huge difference. (explain)

Radeon HD 3870 X2 1GB		26400 Mpixels/sec
Radeon R9 M295X		24000 Mpixels/sec
	Difference: 2400 (10%)

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 (measured in MB per second) that can be transferred over the external memory interface in one second. It is calculated by multiplying the card's bus width by its memory speed. If it uses DDR type memory, it should be multiplied by 2 again. If DDR5, multiply by 4 instead. The better the bandwidth is, the better the card will be in general. It especially helps with AA, HDR and high resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that can be processed per second. This figure is worked out by multiplying the total texture units by the core speed of the chip. The higher this number, the better the graphics 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 most pixels that the graphics chip can possibly record to its local memory in a 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 - aka Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel output rate is also dependant on quite a few other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to get to the max fill rate.