GeForce 840M vs Radeon R5 M255

Intro

Compare those specs to the Radeon R5 M255, which comes with core speeds of 940 MHz on the GPU, and 1000 MHz on the 2048 MB of DDR3 RAM. It features 320 SPUs along with 20 Texture Address Units and 8 Rasterization Operator Units.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Memory Bandwidth

Both cards have exactly the same memory bandwidth, so theoretically they should perform the same. (explain)

Texel Rate

The GeForce 840M is quite a bit (approximately 31%) more effective at anisotropic filtering than the Radeon R5 M255. (explain)

GeForce 840M		24696 Mtexels/sec
Radeon R5 M255		18800 Mtexels/sec
	Difference: 5896 (31%)

Pixel Rate

If running with lots of anti-aliasing is important to you, then the GeForce 840M is a better choice, not by a very large margin though. (explain)

GeForce 840M		8232 Mpixels/sec
Radeon R5 M255		7520 Mpixels/sec
	Difference: 712 (9%)

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 largest amount of data (measured in MB per second) that can be moved past the external memory interface within a second. It is calculated by multiplying the card's interface width by its memory speed. If it uses DDR type memory, it should be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The higher the card's 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 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 processed per second.

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