Radeon HD 4850 512MB vs Radeon R5 M255

Intro

Compare those specifications to the Radeon R5 M255, which has GPU clock speed of 940 MHz, and 2048 MB of DDR3 RAM running at 1000 MHz through a 64-bit bus. It also is made up of 320 SPUs, 20 Texture Address Units, and 8 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Memory Bandwidth

In theory, the Radeon HD 4850 512MB is 297% faster than the Radeon R5 M255 in general, due to its greater data rate. (explain)

Radeon HD 4850 512MB		63552 MB/sec
Radeon R5 M255		16000 MB/sec
	Difference: 47552 (297%)

Texel Rate

The Radeon HD 4850 512MB should be much (more or less 33%) faster with regards to AF than the Radeon R5 M255. (explain)

Radeon HD 4850 512MB		25000 Mtexels/sec
Radeon R5 M255		18800 Mtexels/sec
	Difference: 6200 (33%)

Pixel Rate

The Radeon HD 4850 512MB should be quite a bit (about 33%) more effective at anti-aliasing than the Radeon R5 M255, and also should be capable of handling higher screen resolutions more effectively. (explain)

Radeon HD 4850 512MB		10000 Mpixels/sec
Radeon R5 M255		7520 Mpixels/sec
	Difference: 2480 (33%)

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 maximum amount of information (measured in MB per second) that can be transported past the external memory interface in one second. The number is worked out by multiplying the bus width by its memory clock speed. In the case of DDR memory, it must be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The better the memory bandwidth, the better the card will be in general. It especially helps with anti-aliasing, HDR and higher screen resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that are processed in one second. This is calculated by multiplying the total number of texture units of the card by the core clock speed of the chip. The better the texel rate, the better the graphics card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels in a second.

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