Radeon HD 6870 vs Radeon R9 M390X

Intro

Compare that to the Radeon R9 M390X, which has a core clock speed of 723 MHz and a GDDR5 memory frequency of 1250 MHz. It also uses a 256-bit bus, and uses a 28 nm design. It features 2048 SPUs, 128 TAUs, and 32 ROPs.

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

Theoretically speaking, the Radeon R9 M390X will be 19% quicker than the Radeon HD 6870 in general, due to its greater data rate. (explain)

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

Texel Rate

The Radeon R9 M390X will be quite a bit (about 84%) faster with regards to AF than the Radeon HD 6870. (explain)

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

Pixel Rate

The Radeon HD 6870 will be a lot (approximately 24%) faster with regards to full screen anti-aliasing than the Radeon R9 M390X, and capable of handling higher resolutions more effectively. (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 maximum amount of information (in units of megabytes per second) that can be transported across the external memory interface in one second. It's worked out by multiplying the card's interface width by the speed of its memory. In the case of DDR memory, it should be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The higher 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 number of texture map elements (texels) that are processed per second. This number is calculated by multiplying the total amount of texture units by the core clock speed of the chip. The better the texel rate, the better the video card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels in one second.

Pixel Rate: Pixel rate is the most pixels the graphics card could 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 Render Output Units by the clock 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 output rate is also dependant on lots of other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the potential to get to the max fill rate.