Radeon HD 7870 vs Radeon R9 M385X

Intro

Compare those specs to the Radeon R9 M385X, which has a core clock frequency of 1100 MHz and a GDDR5 memory speed of 1500 MHz. It also makes use of a 128-bit memory bus, and uses a 28 nm design. It features 896 SPUs, 56 TAUs, and 16 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Memory Bandwidth

Theoretically speaking, the Radeon HD 7870 should be a lot faster than the Radeon R9 M385X overall. (explain)

Radeon HD 7870		153600 MB/sec
Radeon R9 M385X		96000 MB/sec
	Difference: 57600 (60%)

Texel Rate

The Radeon HD 7870 will be quite a bit (about 30%) more effective at texture filtering than the Radeon R9 M385X. (explain)

Radeon HD 7870		80000 Mtexels/sec
Radeon R9 M385X		61600 Mtexels/sec
	Difference: 18400 (30%)

Pixel Rate

The Radeon HD 7870 should be much (about 82%) better at anti-aliasing than the Radeon R9 M385X, and also should be capable of handling higher screen resolutions better. (explain)

Radeon HD 7870		32000 Mpixels/sec
Radeon R9 M385X		17600 Mpixels/sec
	Difference: 14400 (82%)

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.

Price Comparison

Specifications

Memory Bandwidth: Memory bandwidth is the max amount of information (in units of megabytes per second) that can be moved across the external memory interface within a second. It is worked out by multiplying the card's interface width by its memory speed. If it uses DDR type RAM, it must be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The better the memory bandwidth, the better 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 are processed in one second. This number is calculated by multiplying the total number of texture units of the card by the core clock speed of the chip. The better this number, the better the card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels in a second.

Pixel Rate: Pixel rate is the most pixels that the graphics 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 number of Render Output Units by the clock speed of the card. 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, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to get to the maximum fill rate.