Radeon HD 7870 vs Radeon R9 M275X

Intro

Compare those specifications to the Radeon R9 M275X, which features a clock frequency of 900 MHz and a GDDR5 memory frequency of 1125 MHz. It also makes use of a 128-bit memory bus, and makes use of a 28 nm design. It is comprised of 640 SPUs, 40 TAUs, and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon R9 M275X		50 Watts
Radeon HD 7870		175 Watts
	Difference: 125 Watts (250%)

Memory Bandwidth

Theoretically, the Radeon HD 7870 should perform quite a bit faster than the Radeon R9 M275X overall. (explain)

Radeon HD 7870		153600 MB/sec
Radeon R9 M275X		72000 MB/sec
	Difference: 81600 (113%)

Texel Rate

The Radeon HD 7870 will be a lot (more or less 122%) better at AF than the Radeon R9 M275X. (explain)

Radeon HD 7870		80000 Mtexels/sec
Radeon R9 M275X		36000 Mtexels/sec
	Difference: 44000 (122%)

Pixel Rate

The Radeon HD 7870 is much (approximately 122%) faster with regards to FSAA than the Radeon R9 M275X, and also should be capable of handling higher resolutions without losing too much performance. (explain)

Radeon HD 7870		32000 Mpixels/sec
Radeon R9 M275X		14400 Mpixels/sec
	Difference: 17600 (122%)

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 data (counted in MB per second) that can be transferred over the external memory interface within a second. It is worked out by multiplying the bus width by its memory speed. If the card has DDR type RAM, it must be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The better the bandwidth is, the faster 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 can be processed in one second. This figure is worked out by multiplying the total texture units of the card by the core speed of the chip. The better the texel rate, the better the 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 number of pixels the video card could possibly write to the local memory in one second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the amount of Render Output Units by the the core clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel rate is also dependant on lots of other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to get to the max fill rate.