Radeon HD 4790 vs Radeon R5 M255

Intro

Compare all that to the Radeon R5 M255, which has core clock 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

Hide Graphs

Power Usage and Theoretical Benchmarks

Memory Bandwidth

In theory, the Radeon HD 4790 should be a lot faster than the Radeon R5 M255 in general. (explain)

Radeon HD 4790		102400 MB/sec
Radeon R5 M255		16000 MB/sec
	Difference: 86400 (540%)

Texel Rate

The Radeon HD 4790 is a little bit (approximately 2%) more effective at anisotropic filtering than the Radeon R5 M255. (explain)

Radeon HD 4790		19200 Mtexels/sec
Radeon R5 M255		18800 Mtexels/sec
	Difference: 400 (2%)

Pixel Rate

If using a high resolution is important to you, then the Radeon HD 4790 is a better choice, by a large margin. (explain)

Radeon HD 4790		9600 Mpixels/sec
Radeon R5 M255		7520 Mpixels/sec
	Difference: 2080 (28%)

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 (counted in megabytes per second) that can be transferred across the external memory interface within a second. The number is calculated by multiplying the bus width by its memory clock speed. If the card has DDR RAM, it should be multiplied by 2 again. If 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 higher screen resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that can be processed in one second. This number is calculated by multiplying the total number of texture units 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 per second.

Pixel Rate: Pixel rate is the maximum number of pixels that the graphics card can possibly record to the local memory in one second - measured in millions of pixels per second. The number 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 drawing the pixels (image) on the screen. The actual pixel rate is also dependant on quite a few other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the potential to get to the max fill rate.