You have nothing to lose - except possibly programme unreliability and at worst a frazzled processor if you overdo it.
My understanding of this is that processor chips are labelled at the factory depending on their performance on individual test. Due to manufacturing constraints the manufacturer will aim to produce the highest speed processors on the production line but some of them will not be up to the full specification. These processors may be re-labelled and sold as lower speed items. One individual chip may be quite a bit better than another even though they may both share the same speed rating.
Try it and see but don't blame anyone if it fails. (You may need to fit a better fan than the one that came with it as uprating the speed will increase the heat production).
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May the Force be with you - and may Gravity treat you gently..
[This message has been edited by Skycop (edited 09 January 2000).]