Radeon HD 6770 vs Radeon R5 M255

Intro

Compare all that to the Radeon R5 M255, which has a clock frequency of 940 MHz and a DDR3 memory speed of 1000 MHz. It also features a 64-bit bus, and uses a 28 nm design. It features 320 SPUs, 20 TAUs, and 8 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Memory Bandwidth

The Radeon HD 6770 should in theory be a lot faster than the Radeon R5 M255 overall. (explain)

Radeon HD 6770		67200 MB/sec
Radeon R5 M255		16000 MB/sec
	Difference: 51200 (320%)

Texel Rate

The Radeon HD 6770 is much (about 91%) more effective at texture filtering than the Radeon R5 M255. (explain)

Radeon HD 6770		36000 Mtexels/sec
Radeon R5 M255		18800 Mtexels/sec
	Difference: 17200 (91%)

Pixel Rate

If using a high resolution is important to you, then the Radeon HD 6770 is the winner, and very much so. (explain)

Radeon HD 6770		14400 Mpixels/sec
Radeon R5 M255		7520 Mpixels/sec
	Difference: 6880 (91%)

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 information (in units of megabytes per second) that can be transported across the external memory interface in one second. The number is calculated by multiplying the card's interface width by the speed of its memory. If it uses DDR type RAM, it should be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The better the bandwidth is, the better the card will be in general. It especially helps with anti-aliasing, 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 is worked out by multiplying the total texture units of the card by the core clock speed of the chip. The higher this number, the better the video card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels in one second.

Pixel Rate: Pixel rate is the maximum number of pixels that the graphics chip can possibly write to its local memory in a second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the number of Render Output Units by the the core clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel fill rate also depends on lots of other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the potential to get to the maximum fill rate.