Radeon HD 4850 2GB vs Radeon R9 M275X

Intro

Compare all of that to the Radeon R9 M275X, which features a core clock frequency of 900 MHz and a GDDR5 memory speed of 1125 MHz. It also uses a 128-bit memory bus, and makes use of a 28 nm design. It is comprised of 640 SPUs, 40 Texture Address Units, 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 4850 2GB		110 Watts
	Difference: 60 Watts (120%)

Memory Bandwidth

In theory, the Radeon R9 M275X will be 13% quicker than the Radeon HD 4850 2GB in general, due to its greater data rate. (explain)

Radeon R9 M275X		72000 MB/sec
Radeon HD 4850 2GB		63552 MB/sec
	Difference: 8448 (13%)

Texel Rate

The Radeon R9 M275X will be a lot (more or less 44%) more effective at AF than the Radeon HD 4850 2GB. (explain)

Radeon R9 M275X		36000 Mtexels/sec
Radeon HD 4850 2GB		25000 Mtexels/sec
	Difference: 11000 (44%)

Pixel Rate

If using a high screen resolution is important to you, then the Radeon R9 M275X is superior to the Radeon HD 4850 2GB, by a large margin. (explain)

Radeon R9 M275X		14400 Mpixels/sec
Radeon HD 4850 2GB		10000 Mpixels/sec
	Difference: 4400 (44%)

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 megabytes per second) that can be transported past the external memory interface within a second. It's calculated by multiplying the card's bus width by its memory speed. If it uses DDR type memory, it should be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The better the card's memory bandwidth, the better 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 per second. This number is calculated by multiplying the total number of texture units of the card by the core speed of the chip. The better this number, the better the card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed per second.

Pixel Rate: Pixel rate is the maximum number of pixels that the graphics chip could possibly write to the local memory in a second - measured in millions of pixels per second. The number is calculated by multiplying the amount of Render Output Units by the the card's clock speed. 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 quite a few other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the ability to reach the maximum fill rate.