[Mikegrenwick]

Is it possible to overclock a Dual 2.0 G5? I am currently under the impression that the Dual 2.7 is just an overclocked 2.3...is this correct?

[Luca]

Short answer: No, it's not easy to overclock a G5 and even if you could, it wouldn't show much benefit.

Long answer: It's technically possible, but this line of thinking belies a basic misunderstanding of how processors work. All processors are technically capable of running at pretty much any speed, but they are only stable up to a certain speed. IBM has a factory where they churn out G5 processors. They test them and assign them a rated speed. Some are stable at 2.7 GHz, and they're thrown in the 2.7 GHz bin. Others are not stable enough for IBM's tests and instead get put in the 2.3 GHz bin. The largest number are put in the 2.0 GHz bin.

So, the dual 2.7 GHz machine is no more an overclocked dual 2.3 than the dual 2.3 is an underclocked dual 2.7. The processors you get are simply running at their highest stable speed.

With the right cooling equipment, you can get your CPUs to run at a higher clock speed and still be stable. And maybe your dual 2.0 can run fine somewhere around 2.1-2.2 GHz, but not at 2.3 GHz. I don't know. What I can tell you is that with a Mac, it's very difficult and it's not worth it. PCs are a very different story because you don't have to chagne any hardware, you just adjust settings in the BIOS. With a Mac you would have to solder things.

Bottom line: It's technically possible, but it's not worth it.