Radeon R9 280X vs Radeon R9 M390X

Intro

Compare all 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 makes use of a 256-bit memory bus, and makes use of a 28 nm design. It features 2048 SPUs, 128 Texture Address Units, and 32 Raster Operation Units.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon R9 M390X		125 Watts
Radeon R9 280X		250 Watts
	Difference: 125 Watts (100%)

Memory Bandwidth

Performance-wise, the Radeon R9 280X should theoretically be a lot superior to the Radeon R9 M390X overall. (explain)

Radeon R9 280X		288000 MB/sec
Radeon R9 M390X		160000 MB/sec
	Difference: 128000 (80%)

Texel Rate

The Radeon R9 280X should be a small bit (approximately 18%) better at AF than the Radeon R9 M390X. (explain)

Radeon R9 280X		108800 Mtexels/sec
Radeon R9 M390X		92544 Mtexels/sec
	Difference: 16256 (18%)

Pixel Rate

The Radeon R9 280X should be a small bit (about 18%) better at full screen anti-aliasing than the Radeon R9 M390X, and should be capable of handling higher resolutions while still performing well. (explain)

Radeon R9 280X		27200 Mpixels/sec
Radeon R9 M390X		23136 Mpixels/sec
	Difference: 4064 (18%)

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 a second. It's worked out by multiplying the card's interface width by its memory clock speed. If it uses DDR type memory, it must 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 number of texture map elements (texels) that are processed per second. This number is calculated by multiplying the total 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 handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed per second.

Pixel Rate: Pixel rate is the most pixels that the graphics card can possibly write to its local memory per second - measured in millions of pixels per second. The number is calculated by multiplying the amount of ROPs by the clock speed of the card. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel fill rate also depends on quite a few other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the potential to reach the max fill rate.