..yeah i know this an old post im referring to, but felt someone should make the correction..
OCP is not over clock protecion (although it is a form of protection and is related to overclocking, lol)
OCP is a fail-safe limit imposed on hardware to prevent you from pushing too much current through the power plane. OCP is overcurrent protection.
Sometimes you will also see OVP mentioned/discussed/measured in the context of extreme benching. They both do the same thing in that they set an upper limit, one for current (I - measured in amperes) and the other for voltage (v - measure in volts). If/when you exceed the set limit for OCP/OVP, it will trip the protection. If that happens, basically your card will shut down in order to protect itself from damage. Again, it is a fail-safe mechanism. I have only ever had to raise OCP or OVP one time in my life, and that was with an 8800GT at -180c benching session. It is exceedingly unlikely that anyone will ever need to raise these limits who is benching/OCing on air or water. Raising it on air/water will not hurt your card, in and of itself. It will essentially do nothing, because you will not come close to exceeding the limit to begin with. So, in a nutshell, you can basically ignore that setting unless you are benching subzero (and even then you probably wont need to adjust it too often)