Radeon R9 390X 8G vs Radeon R9 M275X

Intro

Compare those specs to the Radeon R9 M275X, which comes with core clock speeds of 900 MHz on the GPU, and 1125 MHz on the 2048 MB of GDDR5 memory. It features 640 SPUs along with 40 Texture Address Units and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

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

Memory Bandwidth

Theoretically, the Radeon R9 390X 8G should be a lot faster than the Radeon R9 M275X in general. (explain)

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

Texel Rate

The Radeon R9 390X 8G should be much (about 413%) faster with regards to texture filtering than the Radeon R9 M275X. (explain)

Radeon R9 390X 8G		184800 Mtexels/sec
Radeon R9 M275X		36000 Mtexels/sec
	Difference: 148800 (413%)

Pixel Rate

The Radeon R9 390X 8G will be a lot (approximately 367%) better at full screen anti-aliasing than the Radeon R9 M275X, and should be capable of handling higher resolutions without losing too much performance. (explain)

Radeon R9 390X 8G		67200 Mpixels/sec
Radeon R9 M275X		14400 Mpixels/sec
	Difference: 52800 (367%)

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 max amount of information (measured in megabytes per second) that can be transported past the external memory interface in a second. It's worked out by multiplying the interface width by its memory clock speed. If the card has DDR memory, the result should be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The higher the memory bandwidth, the better the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.

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

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics card can possibly record to the local memory per second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the amount of Render Output Units by the the card's clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel fill rate also depends on lots of other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to get to the max fill rate.