GeForce 9400 GT 256MB vs GeForce GTX 850M

Intro

Compare those specifications to the GeForce GTX 850M, which comes with GPU core speed of 876 MHz, and 2048 MB of DDR3 RAM set to run at 1000 MHz through a 128-bit bus. It also is comprised of 640 Stream Processors, 40 TAUs, and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GTX 850M		40 Watts
GeForce 9400 GT 256MB		50 Watts
	Difference: 10 Watts (25%)

Memory Bandwidth

Performance-wise, the GeForce GTX 850M should in theory be quite a bit better than the GeForce 9400 GT 256MB overall. (explain)

GeForce GTX 850M		32000 MB/sec
GeForce 9400 GT 256MB		12800 MB/sec
	Difference: 19200 (150%)

Texel Rate

The GeForce GTX 850M will be much (about 696%) better at anisotropic filtering than the GeForce 9400 GT 256MB. (explain)

GeForce GTX 850M		35040 Mtexels/sec
GeForce 9400 GT 256MB		4400 Mtexels/sec
	Difference: 30640 (696%)

Pixel Rate

The GeForce GTX 850M is a lot (more or less 537%) better at FSAA than the GeForce 9400 GT 256MB, and should be able to handle higher screen resolutions while still performing well. (explain)

GeForce GTX 850M		14016 Mpixels/sec
GeForce 9400 GT 256MB		2200 Mpixels/sec
	Difference: 11816 (537%)

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 data (measured in megabytes per second) that can be transported past the external memory interface in a second. The number is calculated by multiplying the interface width by the speed of its memory. In the case of DDR type RAM, it should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The higher the bandwidth is, the better the card will be in general. It especially helps with AA, HDR and high resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that can be applied in one second. This number is calculated by multiplying the total amount of texture units by the core 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 most pixels the graphics card could possibly write to its local memory in one second - measured in millions of pixels per second. The number is worked out by multiplying the amount of colour ROPs by the the core speed of the card. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel output rate also depends on many other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to reach the maximum fill rate.