GeForce 820M vs Radeon R5 M255

Intro

Compare all that to the Radeon R5 M255, which comes with clock 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 the exact same bandwidth, so in theory they should perform the same. (explain)

Texel Rate

The Radeon R5 M255 is quite a bit (more or less 63%) faster with regards to texture filtering than the GeForce 820M. (explain)

Radeon R5 M255		18800 Mtexels/sec
GeForce 820M		11504 Mtexels/sec
	Difference: 7296 (63%)

Pixel Rate

The Radeon R5 M255 will be quite a bit (about 161%) more effective at FSAA than the GeForce 820M, and also should be capable of handling higher resolutions more effectively. (explain)

Radeon R5 M255		7520 Mpixels/sec
GeForce 820M		2876 Mpixels/sec
	Difference: 4644 (161%)

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 information (measured in megabytes per second) that can be transported across the external memory interface in a second. It's worked out by multiplying the card's interface width by its memory speed. If it uses DDR RAM, it must be multiplied by 2 again. If it uses 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 texture map elements (texels) that can be processed in one second. This figure is calculated by multiplying the total amount of texture units by the core speed of the chip. The higher this number, the better the graphics card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels per second.

Pixel Rate: Pixel rate is the maximum amount 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 Raster Operations Pipelines by the the core speed of the card. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel output rate is also dependant on many other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to reach the maximum fill rate.