Radeon HD 6770 1GB vs Radeon R5 M255

Intro

Compare those specifications to the Radeon R5 M255, which has core speeds of 940 MHz on the GPU, and 1000 MHz on the 2048 MB of DDR3 memory. It features 320 SPUs as well as 20 Texture Address Units and 8 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Memory Bandwidth

The Radeon HD 6770 1GB should in theory be much faster than the Radeon R5 M255 in general. (explain)

Radeon HD 6770 1GB		67200 MB/sec
Radeon R5 M255		16000 MB/sec
	Difference: 51200 (320%)

Texel Rate

The Radeon HD 6770 1GB will be quite a bit (approximately 91%) better at AF than the Radeon R5 M255. (explain)

Radeon HD 6770 1GB		36000 Mtexels/sec
Radeon R5 M255		18800 Mtexels/sec
	Difference: 17200 (91%)

Pixel Rate

If running with a high screen resolution is important to you, then the Radeon HD 6770 1GB is the winner, by far. (explain)

Radeon HD 6770 1GB		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: Bandwidth is the largest amount of data (counted in MB per second) that can be transported over the external memory interface within a second. It is calculated by multiplying the interface width by its memory speed. In the case of DDR memory, it must be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The better the bandwidth is, the faster the card will be in general. It especially helps with AA, HDR and high resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that can be applied in one second. This number is worked out by multiplying the total number of texture units of the card by the core speed of the chip. The higher the texel rate, the better the graphics card will be at 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 the graphics card can possibly write to its local memory in one second - measured in millions of pixels per second. The number is worked out by multiplying the number of Render Output Units by the the core speed of the card. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel output rate is also dependant on many other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the potential to reach the maximum fill rate.