GeForce 9400 GT 256MB vs GeForce GTX 870M

Intro

Compare that to the GeForce GTX 870M, which comes with a core clock speed of 941 MHz and a GDDR5 memory frequency of 1000 MHz. It also features a 192-bit bus, and uses a 28 nm design. It is comprised of 1344 SPUs, 112 TAUs, and 24 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce 9400 GT 256MB		50 Watts
GeForce GTX 870M		110 Watts
	Difference: 60 Watts (120%)

Memory Bandwidth

Theoretically speaking, the GeForce GTX 870M will be 650% quicker than the GeForce 9400 GT 256MB in general, because of its greater bandwidth. (explain)

GeForce GTX 870M		96000 MB/sec
GeForce 9400 GT 256MB		12800 MB/sec
	Difference: 83200 (650%)

Texel Rate

The GeForce GTX 870M is much (more or less 2295%) faster with regards to AF than the GeForce 9400 GT 256MB. (explain)

GeForce GTX 870M		105392 Mtexels/sec
GeForce 9400 GT 256MB		4400 Mtexels/sec
	Difference: 100992 (2295%)

Pixel Rate

The GeForce GTX 870M should be quite a bit (approximately 927%) faster with regards to anti-aliasing than the GeForce 9400 GT 256MB, and should be capable of handling higher screen resolutions without slowing down too much. (explain)

GeForce GTX 870M		22584 Mpixels/sec
GeForce 9400 GT 256MB		2200 Mpixels/sec
	Difference: 20384 (927%)

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 MB per second) that can be transported across the external memory interface in one second. The number is calculated by multiplying the bus width by its memory clock speed. If it uses DDR type RAM, it must be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The higher the 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 number of texture map elements (texels) that are processed per second. This is worked out by multiplying the total texture units of the card by the core speed of the chip. The higher this number, the better the graphics card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels in one second.

Pixel Rate: Pixel rate is the most pixels that the graphics chip could possibly write to its local memory per second - measured in millions of pixels per second. The figure is worked out by multiplying the number of Render Output Units by the the core clock speed. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel fill rate is also dependant on quite a few other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to get to the max fill rate.