GeForce 820M vs GeForce 9400 GT 256MB

Intro

Compare all of that to the GeForce 9400 GT 256MB, which uses a 65 nm design. nVidia has clocked the core frequency at 550 MHz. The GDDR2 memory works at a speed of 400 MHz on this card. It features 16 SPUs along with 8 Texture Address Units and 4 ROPs.

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

The GeForce 820M, in theory, should be 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 will be a lot (approximately 161%) better at AF than the GeForce 9400 GT 256MB. (explain)

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

Pixel Rate

The GeForce 820M should be quite a bit (approximately 31%) better at anti-aliasing than the GeForce 9400 GT 256MB, and also will be capable of handling higher resolutions more effectively. (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 largest amount of information (in units of megabytes per second) that can be transported across the external memory interface within a second. It's worked out by multiplying the card's bus width by its memory clock speed. If it uses DDR RAM, it must be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The better the bandwidth is, the better the card will be in general. It especially helps with AA, High Dynamic Range and higher screen resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that can be processed in one second. This number is worked out by multiplying the total texture units by the core clock speed of the chip. The better this number, the better the card will be at 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 graphics card can possibly write to the local memory per second - measured in millions of pixels per second. The number is worked out by multiplying the amount of Render Output Units by the the core speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel output rate also depends on quite a few other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to reach the max fill rate.