Radeon HD 4890 1GB vs Radeon R9 M275X

Intro

Compare those specifications to the Radeon R9 M275X, which makes use of a 28 nm design. AMD has clocked the core frequency at 900 MHz. The GDDR5 memory works at a frequency of 1125 MHz on this particular card. It features 640 SPUs along with 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 4890 1GB		190 Watts
	Difference: 140 Watts (280%)

Memory Bandwidth

Performance-wise, the Radeon HD 4890 1GB should theoretically be much superior to the Radeon R9 M275X overall. (explain)

Radeon HD 4890 1GB		124800 MB/sec
Radeon R9 M275X		72000 MB/sec
	Difference: 52800 (73%)

Texel Rate

The Radeon HD 4890 1GB will be a little bit (about 11%) better at anisotropic filtering than the Radeon R9 M275X. (explain)

Radeon HD 4890 1GB		40000 Mtexels/sec
Radeon R9 M275X		36000 Mtexels/sec
	Difference: 4000 (11%)

Pixel Rate

If using high levels of AA is important to you, then the Radeon HD 4890 1GB is the winner, but not by far. (explain)

Radeon HD 4890 1GB		16000 Mpixels/sec
Radeon R9 M275X		14400 Mpixels/sec
	Difference: 1600 (11%)

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 max amount of information (measured in megabytes per second) that can be transferred past the external memory interface within a second. It's worked out by multiplying the bus width by its memory clock speed. If it uses DDR RAM, the result should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The better the bandwidth is, the better the card will be in general. It especially helps with AA, High Dynamic Range and high resolutions.

Texel Rate: Texel rate is the maximum amount 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 higher the texel rate, 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 record to its local memory per second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the number of Render Output Units by the clock speed of the card. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel rate is also dependant on quite a few other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the potential to get to the maximum fill rate.