Radeon R9 390 8G vs Radeon R9 M275X

Intro

Compare those specs to the Radeon R9 M275X, which has a core clock frequency of 900 MHz and a GDDR5 memory frequency of 1125 MHz. It also features a 128-bit bus, and uses a 28 nm design. It is made up of 640 SPUs, 40 Texture Address Units, and 16 Raster Operation Units.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon R9 M275X		50 Watts
Radeon R9 390 8G		275 Watts
	Difference: 225 Watts (450%)

Memory Bandwidth

As far as performance goes, the Radeon R9 390 8G should in theory be much better than the Radeon R9 M275X overall. (explain)

Radeon R9 390 8G		384000 MB/sec
Radeon R9 M275X		72000 MB/sec
	Difference: 312000 (433%)

Texel Rate

The Radeon R9 390 8G will be much (approximately 344%) better at AF than the Radeon R9 M275X. (explain)

Radeon R9 390 8G		160000 Mtexels/sec
Radeon R9 M275X		36000 Mtexels/sec
	Difference: 124000 (344%)

Pixel Rate

The Radeon R9 390 8G is a lot (more or less 344%) better at AA than the Radeon R9 M275X, and also should be capable of handling higher resolutions better. (explain)

Radeon R9 390 8G		64000 Mpixels/sec
Radeon R9 M275X		14400 Mpixels/sec
	Difference: 49600 (344%)

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 (measured in megabytes per second) that can be transferred past the external memory interface in one second. It's worked out by multiplying the bus width by its memory speed. If it uses DDR type RAM, the result should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The better the memory bandwidth, the faster the card will be in general. It especially helps with anti-aliasing, HDR and higher screen resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that can be processed per second. This is calculated by multiplying the total amount of texture units by the core speed of the chip. The better this number, the better the 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 maximum number of pixels that the graphics chip could possibly write to its local memory in one second - measured in millions of pixels per second. The figure is calculated by multiplying the number of Render Output Units by the the card's clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel rate also depends on lots of other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the ability to reach the max fill rate.