GeForce 9800 GX2 vs GeForce GTX 660

Intro

Compare those specs to the GeForce GTX 660, which has GPU core speed of 980 MHz, and 2048 MB of GDDR5 RAM set to run at 1502 MHz through a 192-bit bus. It also is comprised of 960 Stream Processors, 80 Texture Address Units, and 24 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GTX 660		140 Watts
GeForce 9800 GX2		197 Watts
	Difference: 57 Watts (41%)

Memory Bandwidth

As far as performance goes, the GeForce GTX 660 should in theory be a small bit better than the GeForce 9800 GX2 overall. (explain)

GeForce GTX 660		144192 MB/sec
GeForce 9800 GX2		128000 MB/sec
	Difference: 16192 (13%)

Texel Rate

The GeForce GTX 660 will be a little bit (more or less 2%) more effective at AF than the GeForce 9800 GX2. (explain)

GeForce GTX 660		78400 Mtexels/sec
GeForce 9800 GX2		76800 Mtexels/sec
	Difference: 1600 (2%)

Pixel Rate

The GeForce GTX 660 should be much (about 23%) faster with regards to FSAA than the GeForce 9800 GX2, and also will be able to handle higher screen resolutions without losing too much performance. (explain)

GeForce GTX 660		23520 Mpixels/sec
GeForce 9800 GX2		19200 Mpixels/sec
	Difference: 4320 (23%)

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 largest amount of data (counted in MB per second) that can be moved over the external memory interface within a second. It's worked out by multiplying the card's bus width by its memory speed. If the card has DDR memory, the result should be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The higher the memory bandwidth, the faster the card will be in general. It especially helps with AA, HDR and high resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that can be processed in one second. This figure is calculated by multiplying the total texture units of the card 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 that the graphics chip could possibly record to the local memory in a second - measured in millions of pixels per second. The figure is calculated by multiplying the number of Render Output Units by the the core speed of the card. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel output rate is also dependant on many other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to reach the max fill rate.