Radeon HD 7850 vs Radeon R9 M290X

Intro

Compare all that to the Radeon R9 M290X, which comes with GPU core speed of 850 MHz, and 4096 MB of GDDR5 RAM set to run at 1200 MHz through a 256-bit bus. It also is comprised of 1280 Stream Processors, 80 Texture Address Units, and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon R9 M290X		100 Watts
Radeon HD 7850		130 Watts
	Difference: 30 Watts (30%)

Memory Bandwidth

Both cards have exactly the same bandwidth, so in theory they should perform the same. (explain)

Texel Rate

The Radeon R9 M290X will be quite a bit (approximately 24%) more effective at anisotropic filtering than the Radeon HD 7850. (explain)

Radeon R9 M290X		68000 Mtexels/sec
Radeon HD 7850		55040 Mtexels/sec
	Difference: 12960 (24%)

Pixel Rate

If running with lots of anti-aliasing is important to you, then the Radeon HD 7850 is a better choice, though not by far. (explain)

Radeon HD 7850		27520 Mpixels/sec
Radeon R9 M290X		27200 Mpixels/sec
	Difference: 320 (1%)

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 largest amount of information (measured in MB per second) that can be transferred over the external memory interface within a second. It's calculated by multiplying the bus width by its memory speed. If it uses DDR type RAM, it must be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The higher the card's memory bandwidth, the faster the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and higher screen resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that are processed in one second. This figure is worked out by multiplying the total amount of texture units by the core clock speed of the chip. The better this number, the better the video 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 most pixels that the graphics chip could possibly write to the 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 - sometimes also referred to as Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel output rate also depends on lots of other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the ability to reach the max fill rate.