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The author defines it "a software turbo switch" - hence the name. In comparison to CPU Killer, it should be said that Turbo is genuine freeware, so it is not crippled in any way.
Software Review - Pros
Slows down your machine from 1 to 99%, as it is supposed to. As I'm not much into gaming, I rarely use it, and when I do, it's mainly for testing purposes. The graphical user interface is somewhat plain, maybe even crude. I definitely like that, and it is particularly consistent with a small utility like this one. There's enough bloatware in circulation already.
Software Review - Cons
As with all such programs, the main problem is represented by the smoothness of the slow-down effect. This utility is not the smoothest one around, I would say, so it may produce some jerky operation if used in gaming, I suppose. But that would be saying too much, really, as I haven't tested it with any game. So you will have to try it out yourself.