GeForce 9800 GX2 vs GeForce GTX 850M

Intro

Compare that to the GeForce GTX 850M, which has core speeds of 876 MHz on the GPU, and 1000 MHz on the 2048 MB of DDR3 RAM. It features 640 SPUs as well as 40 Texture Address Units and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GTX 850M		40 Watts
GeForce 9800 GX2		197 Watts
	Difference: 157 Watts (393%)

Memory Bandwidth

The GeForce 9800 GX2, in theory, should perform a lot faster than the GeForce GTX 850M overall. (explain)

GeForce 9800 GX2		128000 MB/sec
GeForce GTX 850M		32000 MB/sec
	Difference: 96000 (300%)

Texel Rate

The GeForce 9800 GX2 will be much (about 119%) more effective at anisotropic filtering than the GeForce GTX 850M. (explain)

GeForce 9800 GX2		76800 Mtexels/sec
GeForce GTX 850M		35040 Mtexels/sec
	Difference: 41760 (119%)

Pixel Rate

The GeForce 9800 GX2 should be much (about 37%) faster with regards to FSAA than the GeForce GTX 850M, and able to handle higher screen resolutions while still performing well. (explain)

GeForce 9800 GX2		19200 Mpixels/sec
GeForce GTX 850M		14016 Mpixels/sec
	Difference: 5184 (37%)

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.

One or more cards in this comparison are multi-core. This means that their bandwidth, texel and pixel rates are theoretically doubled - this does not mean the card will actually perform twice as fast, but only that it should in theory be able to. Actual game benchmarks will give a more accurate idea of what it's capable of.

Price Comparison

Specifications

Memory Bandwidth: Memory bandwidth is the largest amount of information (counted in MB per second) that can be moved past the external memory interface in a second. The number is calculated by multiplying the bus width by its memory clock speed. If the card has DDR RAM, it must be multiplied by 2 again. If DDR5, multiply by 4 instead. The better the bandwidth is, the faster 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 number of texture map elements (texels) that are applied in one second. This number is calculated by multiplying the total number of texture units by the core speed of the chip. The higher the texel rate, the better the card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied per second.

Pixel Rate: Pixel rate is the maximum number of pixels that the graphics card can possibly write to the local memory per second - measured in millions of pixels per second. The figure is calculated by multiplying the amount of Raster Operations Pipelines by the the card's clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel output rate also depends on lots of other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to get to the max fill rate.