GeForce GT 420 vs GeForce GTX 850M

Intro

Compare those specifications to the GeForce GTX 850M, which uses a 28 nm design. nVidia has set the core frequency at 876 MHz. The DDR3 memory works at a frequency of 1000 MHz on this particular model. 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 GT 420		50 Watts
	Difference: 10 Watts (25%)

Memory Bandwidth

Performance-wise, the GeForce GTX 850M should theoretically be a small bit superior to the GeForce GT 420 in general. (explain)

GeForce GTX 850M		32000 MB/sec
GeForce GT 420		28800 MB/sec
	Difference: 3200 (11%)

Texel Rate

The GeForce GTX 850M should be a lot (more or less 526%) better at anisotropic filtering than the GeForce GT 420. (explain)

GeForce GTX 850M		35040 Mtexels/sec
GeForce GT 420		5600 Mtexels/sec
	Difference: 29440 (526%)

Pixel Rate

If running with a high screen resolution is important to you, then the GeForce GTX 850M is the winner, by a large margin. (explain)

GeForce GTX 850M		14016 Mpixels/sec
GeForce GT 420		2800 Mpixels/sec
	Difference: 11216 (401%)

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 maximum amount of data (measured in MB per second) that can be transferred over the external memory interface in one second. It's calculated by multiplying the card's interface width by its memory clock speed. In the case of DDR RAM, it must be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The better the memory bandwidth, the faster the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and higher screen resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are applied in one second. This figure is worked out by multiplying the total amount 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 handling 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 record to the local memory per second - measured in millions of pixels per second. The figure is calculated by multiplying the number of Raster Operations Pipelines by the clock speed of the card. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel rate also depends on quite a few other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the ability to get to the max fill rate.