Radeon HD 6870 vs Radeon R9 M390X

Intro

Compare those specs to the Radeon R9 M390X, which has clock speeds of 723 MHz on the GPU, and 1250 MHz on the 4096 MB of GDDR5 memory. It features 2048 SPUs along with 128 Texture Address Units and 32 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon R9 M390X		125 Watts
Radeon HD 6870		151 Watts
	Difference: 26 Watts (21%)

Memory Bandwidth

In theory, the Radeon R9 M390X will be 19% faster than the Radeon HD 6870 overall, because of its higher bandwidth. (explain)

Radeon R9 M390X		160000 MB/sec
Radeon HD 6870		134400 MB/sec
	Difference: 25600 (19%)

Texel Rate

The Radeon R9 M390X will be a lot (about 84%) more effective at anisotropic filtering than the Radeon HD 6870. (explain)

Radeon R9 M390X		92544 Mtexels/sec
Radeon HD 6870		50400 Mtexels/sec
	Difference: 42144 (84%)

Pixel Rate

If using a high resolution is important to you, then the Radeon HD 6870 is the winner, by far. (explain)

Radeon HD 6870		28800 Mpixels/sec
Radeon R9 M390X		23136 Mpixels/sec
	Difference: 5664 (24%)

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 data (in units of megabytes per second) that can be moved across the external memory interface in a second. It is calculated by multiplying the bus width by its memory speed. In the case of DDR type RAM, the result should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The better the card's 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 number of texture map elements (texels) that are processed per second. This number is calculated by multiplying the total texture units by the core clock speed of the chip. The higher this number, the better the graphics card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in one second.

Pixel Rate: Pixel rate is the maximum amount of pixels the video card could possibly record to the local memory in a second - measured in millions of pixels per second. The number is calculated by multiplying the number of colour ROPs by the the core speed of the card. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel fill rate also depends on lots of other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to get to the max fill rate.