GeForce 820M vs GeForce 8800 GTX

Intro

Compare all that to the GeForce 8800 GTX, which features a GPU core clock speed of 575 MHz, and 768 MB of GDDR3 RAM set to run at 900 MHz through a 384-bit bus. It also features 128 SPUs, 64 Texture Address Units, and 24 ROPs.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce 820M		15 Watts
GeForce 8800 GTX		155 Watts
	Difference: 140 Watts (933%)

Memory Bandwidth

As far as performance goes, the GeForce 8800 GTX should theoretically be much superior to the GeForce 820M in general. (explain)

GeForce 8800 GTX		86400 MB/sec
GeForce 820M		16000 MB/sec
	Difference: 70400 (440%)

Texel Rate

The GeForce 8800 GTX will be much (more or less 220%) faster with regards to AF than the GeForce 820M. (explain)

GeForce 8800 GTX		36800 Mtexels/sec
GeForce 820M		11504 Mtexels/sec
	Difference: 25296 (220%)

Pixel Rate

The GeForce 8800 GTX will be quite a bit (about 380%) better at anti-aliasing than the GeForce 820M, and also able to handle higher resolutions more effectively. (explain)

GeForce 8800 GTX		13800 Mpixels/sec
GeForce 820M		2876 Mpixels/sec
	Difference: 10924 (380%)

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 (measured in MB per second) that can be transported over the external memory interface in one second. It is worked out by multiplying the card's bus width by its memory clock speed. 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 AA, High Dynamic Range and high resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that are applied per second. This is worked out by multiplying the total texture units of the card by the core clock speed of the chip. The better the texel rate, the better the graphics card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in a second.

Pixel Rate: Pixel rate is the maximum number of pixels that the graphics card could possibly write to its local memory per second - measured in millions of pixels per second. The figure is calculated by multiplying the amount of Render Output Units by the the card's 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 fill rate is also dependant on many other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the ability to get to the maximum fill rate.