GeForce GTX 660 Ti vs Geforce GTX 680

Intro

Compare that to the Geforce GTX 680, which comes with a clock frequency of 1006 MHz and a GDDR5 memory frequency of 1502 MHz. It also makes use of a 256-bit bus, and uses a 28 nm design. It is made up of 1536 SPUs, 128 Texture Address Units, and 32 ROPs.

(No game benchmarks for this combination yet.)

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GTX 660 Ti		150 Watts
Geforce GTX 680		195 Watts
	Difference: 45 Watts (30%)

Memory Bandwidth

Performance-wise, the Geforce GTX 680 should in theory be a lot superior to the GeForce GTX 660 Ti in general. (explain)

Geforce GTX 680		192256 MB/sec
GeForce GTX 660 Ti		144000 MB/sec
	Difference: 48256 (34%)

Texel Rate

The Geforce GTX 680 will be quite a bit (approximately 26%) faster with regards to anisotropic filtering than the GeForce GTX 660 Ti. (explain)

Geforce GTX 680		128768 Mtexels/sec
GeForce GTX 660 Ti		102480 Mtexels/sec
	Difference: 26288 (26%)

Pixel Rate

The Geforce GTX 680 should be a lot (approximately 47%) faster with regards to AA than the GeForce GTX 660 Ti, and able to handle higher resolutions without slowing down too much. (explain)

Geforce GTX 680		32192 Mpixels/sec
GeForce GTX 660 Ti		21960 Mpixels/sec
	Difference: 10232 (47%)

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: Bandwidth is the maximum amount of data (in units of megabytes per second) that can be transferred over the external memory interface in a second. The number is worked out by multiplying the card's interface width by its memory speed. If it uses DDR RAM, it should be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The higher the card's memory bandwidth, the better 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 are processed per second. This number is calculated by multiplying the total amount of texture units by the core clock speed of the chip. The higher the texel rate, the better the 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 video card could possibly write to its local memory in a second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the amount of ROPs by the the core clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel fill rate is also dependant on many other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to get to the maximum fill rate.