Radeon R9 285 vs Radeon R9 M390X

Intro

Compare those specifications to the Radeon R9 M390X, which makes use of a 28 nm design. AMD has clocked the core speed at 723 MHz. The GDDR5 RAM works at a frequency of 1250 MHz on this model. 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 R9 285		190 Watts
	Difference: 65 Watts (52%)

Memory Bandwidth

Performance-wise, the Radeon R9 285 should theoretically be a little bit superior to the Radeon R9 M390X in general. (explain)

Radeon R9 285		176000 MB/sec
Radeon R9 M390X		160000 MB/sec
	Difference: 16000 (10%)

Texel Rate

The Radeon R9 285 should be a bit (approximately 11%) more effective at texture filtering than the Radeon R9 M390X. (explain)

Radeon R9 285		102816 Mtexels/sec
Radeon R9 M390X		92544 Mtexels/sec
	Difference: 10272 (11%)

Pixel Rate

The Radeon R9 285 should be a lot (more or less 27%) more effective at full screen anti-aliasing than the Radeon R9 M390X, and also will be capable of handling higher screen resolutions better. (explain)

Radeon R9 285		29376 Mpixels/sec
Radeon R9 M390X		23136 Mpixels/sec
	Difference: 6240 (27%)

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: Bandwidth is the largest amount of data (measured in MB per second) that can be transferred over the external memory interface in one second. It's worked out by multiplying the card's interface width by its memory clock speed. If it uses DDR RAM, it should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The better the memory bandwidth, the better the card will be in general. It especially helps with AA, HDR and high resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that can be processed per second. This is worked out by multiplying the total amount of texture units of the card by the core speed of the chip. The better this number, the better the video card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied per second.

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics chip could possibly record to the local memory in a second - measured in millions of pixels per second. The figure is calculated by multiplying the amount of Raster Operations Pipelines by the the card's clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel output rate is also dependant on quite a few other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the ability to get to the maximum fill rate.