Radeon R9 380 4G vs Radeon R9 M390X

Intro

Compare those specifications to the Radeon R9 M390X, which features a clock frequency of 723 MHz and a GDDR5 memory speed of 1250 MHz. It also makes use of a 256-bit bus, and uses a 28 nm design. It is comprised of 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 R9 380 4G		190 Watts
	Difference: 65 Watts (52%)

Memory Bandwidth

The Radeon R9 380 4G should in theory be a bit faster than the Radeon R9 M390X overall. (explain)

Radeon R9 380 4G		182400 MB/sec
Radeon R9 M390X		160000 MB/sec
	Difference: 22400 (14%)

Texel Rate

The Radeon R9 380 4G will be a little bit (about 17%) faster with regards to anisotropic filtering than the Radeon R9 M390X. (explain)

Radeon R9 380 4G		108640 Mtexels/sec
Radeon R9 M390X		92544 Mtexels/sec
	Difference: 16096 (17%)

Pixel Rate

The Radeon R9 380 4G will be quite a bit (more or less 34%) more effective at AA than the Radeon R9 M390X, and also will be capable of handling higher resolutions while still performing well. (explain)

Radeon R9 380 4G		31040 Mpixels/sec
Radeon R9 M390X		23136 Mpixels/sec
	Difference: 7904 (34%)

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 maximum amount of information (in units of MB per second) that can be transferred past the external memory interface in one second. It's worked out by multiplying the card's bus width by the speed of its memory. In the case of DDR RAM, the result should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The better the memory bandwidth, the better the card will be in general. It especially helps with AA, HDR and higher screen resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that can be applied in one second. This number is worked out by multiplying the total number of texture units by the core speed of the chip. The higher this number, the better the 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 that the graphics chip can possibly write to its local memory in a second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the number of colour ROPs by the the core clock speed. ROPs (Raster Operations Pipelines - aka 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, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to reach the maximum fill rate.