Radeon HD 4770 vs Radeon R5 M255

Intro

Compare that to the Radeon R5 M255, which uses a 28 nm design. AMD has set the core speed at 940 MHz. The DDR3 memory runs at a frequency of 1000 MHz on this specific card. It features 320 SPUs along with 20 Texture Address Units and 8 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Memory Bandwidth

The Radeon HD 4770 should in theory perform much faster than the Radeon R5 M255 in general. (explain)

Radeon HD 4770		51200 MB/sec
Radeon R5 M255		16000 MB/sec
	Difference: 35200 (220%)

Texel Rate

The Radeon HD 4770 will be much (more or less 28%) faster with regards to texture filtering than the Radeon R5 M255. (explain)

Radeon HD 4770		24000 Mtexels/sec
Radeon R5 M255		18800 Mtexels/sec
	Difference: 5200 (28%)

Pixel Rate

If using a high screen resolution is important to you, then the Radeon HD 4770 is superior to the Radeon R5 M255, by far. (explain)

Radeon HD 4770		12000 Mpixels/sec
Radeon R5 M255		7520 Mpixels/sec
	Difference: 4480 (60%)

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 max amount of data (in units of MB per second) that can be transferred over the external memory interface in a second. It's calculated by multiplying the bus width by the speed of its memory. If the card has DDR type memory, the result should be multiplied by 2 again. If DDR5, multiply by 4 instead. The better the card's memory bandwidth, the faster 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 applied in one second. This is worked out by multiplying the total number of texture units of the card by the core speed of the chip. The higher this number, the better the video card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied per second.

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