GeForce 9800 GX2 vs GeForce GTX 850M

Intro

Compare that to the GeForce GTX 850M, which features a core clock frequency of 876 MHz and a DDR3 memory frequency of 1000 MHz. It also makes use of a 128-bit bus, and uses a 28 nm design. It is made up of 640 SPUs, 40 Texture Address Units, and 16 Raster Operation Units.

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

Theoretically, the GeForce 9800 GX2 should perform much faster than the GeForce GTX 850M in general. (explain)

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

Texel Rate

The GeForce 9800 GX2 will be quite a bit (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 quite a bit (approximately 37%) more effective at anti-aliasing than the GeForce GTX 850M, and also will be capable of handling higher resolutions better. (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: Bandwidth is the max amount of information (in units of megabytes 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 its memory clock speed. If it uses DDR RAM, the result should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The higher 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 amount of texture map elements (texels) that can be applied per second. This is calculated by multiplying the total number of texture units of the card by the core clock speed of the chip. The higher this number, the better the video card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in a second.

Pixel Rate: Pixel rate is the maximum number of pixels that the graphics card could possibly record to its local memory per second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the amount of Raster Operations Pipelines 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 rate is also dependant on quite a few other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to reach the max fill rate.