Radeon HD 3850 512MB vs Radeon R9 M275X

Intro

Compare those specifications to the Radeon R9 M275X, which has GPU clock speed of 900 MHz, and 2048 MB of GDDR5 RAM running at 1125 MHz through a 128-bit bus. It also is comprised of 640 SPUs, 40 TAUs, and 16 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon R9 M275X		50 Watts
Radeon HD 3850 512MB		75 Watts
	Difference: 25 Watts (50%)

Memory Bandwidth

In theory, the Radeon R9 M275X should be 36% faster than the Radeon HD 3850 512MB in general, due to its higher bandwidth. (explain)

Radeon R9 M275X		72000 MB/sec
Radeon HD 3850 512MB		52992 MB/sec
	Difference: 19008 (36%)

Texel Rate

The Radeon R9 M275X is much (more or less 237%) more effective at AF than the Radeon HD 3850 512MB. (explain)

Radeon R9 M275X		36000 Mtexels/sec
Radeon HD 3850 512MB		10688 Mtexels/sec
	Difference: 25312 (237%)

Pixel Rate

The Radeon R9 M275X will be much (approximately 35%) more effective at full screen anti-aliasing than the Radeon HD 3850 512MB, and also will be capable of handling higher resolutions while still performing well. (explain)

Radeon R9 M275X		14400 Mpixels/sec
Radeon HD 3850 512MB		10688 Mpixels/sec
	Difference: 3712 (35%)

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 data (in units of megabytes per second) that can be moved across the external memory interface within a second. It is worked out by multiplying the card's bus width by the speed of its memory. If it uses DDR RAM, it should be multiplied by 2 once again. If DDR5, multiply by 4 instead. The higher the 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 per second. This number is worked out by multiplying the total amount of texture units of the card by the core clock speed of the chip. The higher this number, the better the graphics card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in one second.

Pixel Rate: Pixel rate is the maximum number of pixels that the graphics chip can possibly write to the local memory in one second - measured in millions of pixels per second. The figure is worked out by multiplying the amount of Raster Operations Pipelines by the the card's clock speed. ROPs (Raster Operations Pipelines - also called 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 of the card - the lower the bandwidth is, the lower the ability to get to the maximum fill rate.