GeForce GTX 580 3GB vs GeForce GTX 850M

Intro

Compare those specs to the GeForce GTX 850M, which has core clock speeds of 876 MHz on the GPU, and 1000 MHz on the 2048 MB of DDR3 memory. It features 640 SPUs along with 40 TAUs and 16 Rasterization Operator Units.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GTX 850M		40 Watts
GeForce GTX 580 3GB		244 Watts
	Difference: 204 Watts (510%)

Memory Bandwidth

In theory, the GeForce GTX 580 3GB should perform quite a bit faster than the GeForce GTX 850M overall. (explain)

GeForce GTX 580 3GB		192384 MB/sec
GeForce GTX 850M		32000 MB/sec
	Difference: 160384 (501%)

Texel Rate

The GeForce GTX 580 3GB is quite a bit (more or less 41%) better at anisotropic filtering than the GeForce GTX 850M. (explain)

GeForce GTX 580 3GB		49408 Mtexels/sec
GeForce GTX 850M		35040 Mtexels/sec
	Difference: 14368 (41%)

Pixel Rate

If running with a high screen resolution is important to you, then the GeForce GTX 580 3GB is the winner, by far. (explain)

GeForce GTX 580 3GB		37056 Mpixels/sec
GeForce GTX 850M		14016 Mpixels/sec
	Difference: 23040 (164%)

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 (in units of MB per second) that can be transported past the external memory interface in a second. The number is worked out by multiplying the bus width by the speed of its memory. In the case of DDR type RAM, 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 high resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are 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 video 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 the video card could possibly write to the local memory in a second - measured in millions of pixels per second. The number is worked out by multiplying the number of ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel output rate also depends on many other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to get to the maximum fill rate.