GeForce 820M vs GeForce 9400 GT 256MB

Intro

Compare those specifications to the GeForce 9400 GT 256MB, which has a GPU core clock speed of 550 MHz, and 256 MB of GDDR2 memory set to run at 400 MHz through a 128-bit bus. It also is comprised 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 9400 GT 256MB		50 Watts
	Difference: 35 Watts (233%)

Memory Bandwidth

In theory, the GeForce 820M should perform quite a bit faster than the GeForce 9400 GT 256MB in general. (explain)

GeForce 820M		16000 MB/sec
GeForce 9400 GT 256MB		12800 MB/sec
	Difference: 3200 (25%)

Texel Rate

The GeForce 820M should be quite a bit (approximately 161%) faster with regards to texture filtering than the GeForce 9400 GT 256MB. (explain)

GeForce 820M		11504 Mtexels/sec
GeForce 9400 GT 256MB		4400 Mtexels/sec
	Difference: 7104 (161%)

Pixel Rate

If running with a high resolution is important to you, then the GeForce 820M is the winner, by a large margin. (explain)

GeForce 820M		2876 Mpixels/sec
GeForce 9400 GT 256MB		2200 Mpixels/sec
	Difference: 676 (31%)

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 (counted in MB per second) that can be transported past the external memory interface within a second. The number is calculated by multiplying the card's bus width by the speed of its memory. If the card has DDR type RAM, it must be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The better the card's memory bandwidth, the better 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 amount of texture map elements (texels) that are applied per second. This figure is worked out by multiplying the total texture units of the card by the core clock speed of the chip. The higher the texel rate, the better the video card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in one second.

Pixel Rate: Pixel rate is the maximum number of pixels the video card can possibly record to its local memory in one second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the amount of colour ROPs by the the core clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel rate is also dependant on lots of other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to reach the max fill rate.