GeForce 820M vs GeForce 8400 GS 512MB

Intro

Compare those specifications to the GeForce 8400 GS 512MB, which features GPU clock speed of 650 MHz, and 512 MB of DDR2 RAM set to run at 400 MHz through a 64-bit bus. It also is comprised of 16 Stream Processors, 8 Texture Address Units, and 4 ROPs.

Display Graphs

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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

The GeForce 820M, in theory, should be a lot faster than the GeForce 8400 GS 512MB in general. (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 (about 121%) faster with regards to AF than the GeForce 8400 GS 512MB. (explain)

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

Pixel Rate

The GeForce 820M should be a little bit (approximately 11%) better at FSAA than the GeForce 8400 GS 512MB, and also will be capable of handling higher resolutions without slowing down too much. (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 (measured in MB per second) that can be transported across the external memory interface within a second. The number is worked out by multiplying the interface width by the speed of its memory. If the card has DDR type RAM, the result should be multiplied by 2 once 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, High Dynamic Range and high resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that can be processed per second. This number is worked out by multiplying the total amount 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 applied per second.

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics chip 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 drawing the pixels (image) on the screen. The actual pixel fill rate also depends on quite a few other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the potential to reach the max fill rate.