Radeon HD 3870 X2 512MB vs Radeon R9 M380

Intro

Compare those specs to the Radeon R9 M380, which has GPU clock speed of 1000 MHz, and 4096 MB of GDDR5 memory set to run at 1500 MHz through a 128-bit bus. It also is made up of 640 SPUs, 40 TAUs, and 16 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Memory Bandwidth

Theoretically speaking, the Radeon HD 3870 X2 512MB will be 20% quicker than the Radeon R9 M380 overall, because of its greater bandwidth. (explain)

Radeon HD 3870 X2 512MB		115200 MB/sec
Radeon R9 M380		96000 MB/sec
	Difference: 19200 (20%)

Texel Rate

The Radeon R9 M380 is much (more or less 52%) more effective at AF than the Radeon HD 3870 X2 512MB. (explain)

Radeon R9 M380		40000 Mtexels/sec
Radeon HD 3870 X2 512MB		26400 Mtexels/sec
	Difference: 13600 (52%)

Pixel Rate

The Radeon HD 3870 X2 512MB will be much (about 65%) more effective at anti-aliasing than the Radeon R9 M380, and also should be capable of handling higher resolutions better. (explain)

Radeon HD 3870 X2 512MB		26400 Mpixels/sec
Radeon R9 M380		16000 Mpixels/sec
	Difference: 10400 (65%)

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 data (counted in megabytes per second) that can be transported over the external memory interface within a second. It is calculated by multiplying the interface width by its memory clock speed. If the card has DDR RAM, it should be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The higher the bandwidth is, the better the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and higher screen resolutions.

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

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics chip can possibly write to its local memory in a second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the amount of Render Output Units by the clock 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 bandwidth is, the lower the ability to reach the max fill rate.