GeForce 820M vs GeForce 8400 GS 512MB

Intro

Compare that to the GeForce 8400 GS 512MB, which has GPU core speed of 650 MHz, and 512 MB of DDR2 memory set to run at 400 MHz through a 64-bit bus. It also is made up of 16 Stream Processors, 8 Texture Address Units, and 4 Raster Operation Units.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce 820M		15 Watts
GeForce 8400 GS 512MB		40 Watts
	Difference: 25 Watts (167%)

Memory Bandwidth

In theory, the GeForce 820M will be 150% quicker than the GeForce 8400 GS 512MB in general, due to its higher bandwidth. (explain)

GeForce 820M		16000 MB/sec
GeForce 8400 GS 512MB		6400 MB/sec
	Difference: 9600 (150%)

Texel Rate

The GeForce 820M will be quite a bit (more or less 121%) better at anisotropic filtering than the GeForce 8400 GS 512MB. (explain)

GeForce 820M		11504 Mtexels/sec
GeForce 8400 GS 512MB		5200 Mtexels/sec
	Difference: 6304 (121%)

Pixel Rate

If running with high levels of AA is important to you, then the GeForce 820M is a better choice, but only just. (explain)

GeForce 820M		2876 Mpixels/sec
GeForce 8400 GS 512MB		2600 Mpixels/sec
	Difference: 276 (11%)

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: Bandwidth is the max amount of data (counted in MB per second) that can be moved across the external memory interface in one second. The number is worked out by multiplying the interface width by the speed of its memory. If the card has DDR RAM, it must be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The better the 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 applied in one second. This number is worked out by multiplying the total amount of texture units 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 could possibly record to the local memory in a second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the amount of Raster Operations Pipelines by the the core clock speed. 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 lots of other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to get to the max fill rate.