cuda = nvidia processing unit. The more the better the faster. Your GTX660 does have 960 of them (my GTX770's do have 1536 each). It's in their specs.

switching / noise reduction: multiple ways possible:

a) the noise only kicks in when the GPU reaches 70*C or up, thats after say 10 mins rendering at 100% (Octane, or LuxRender in GPU mode). In normal use, they're extremely quite. So way one: don't apply large scale GPU rendering when recording sound.

b) put the GPU('s) either in a netgear PCI extender, or in a separate low-end PC (Octane will support network rendering pretty soon). So way two: put the GPU engine somewhere else. Downside: $$$$

c) way three: have a quite low-end and a (noisy) high-end card in your system. You can swich on/off the high-end card at runtime. Downside: I'm afraid this will fully load the low-end card, and low-end does not mean: not noisy. Usually the high-end ones are the quitest, even at full load. And: the lowest amount of VRAM sets the limit for all. So, not recommended.

d) way four: use fluid-cooling instead of air-cooling, especially on the video-cards. This will be my choice, next time.

happy rendering.

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Usually I'm wrong. But to be effective and efficient, I don't need to be correct or accurate.

visit www.aRtBeeWeb.nl (works) or Missing Manuals (tutorials & reviews) - both need an update though