CPU locking
In computer hardware, CPU locking refers the the process of designing a CPU to have a fixed, preset clock multiplier. CPUs can be sold unlocked, locked (but unlockable with some difficulty), or locked to the point where no single individual has been known to successfully unlock it.
AMD's CPU locking practices usually entail the release of unlocked CPUs for early sales of a new model, then the locking of all CPUs of that model thereafter. AMD CPUs are generally unlockable. In contrast, CPUs from Intel are generally released locked. Recent Intel models have proven very resistant to attempts at unlocking. While this has the benefit of preventing fraud in that a CPU can not be passed off as being a faster model than it actually is, it places limits on what speed a consumer chooses to run their CPU at.
Unlocking a CPU is done for one of three reasons:
- To allow a CPU to be underclocked
- To allow a CPU to be overclocked
- To allow the CPU to run at its designed speed with a slower or faster front side bus than its preset clock-multiplier was set with in mind. For example, some individuals have unlocked Athlon XP CPUs for the purposes of manually setting a higher multiplier so the CPU will work at the correct speed with an older (and therefore slower) motherboard.
Unlocking a CPU has its pitfalls: it will invalidate the manufacturer's warranty, and a mistake in the unlocking process can potentially destroy the CPU's ability to function properly. Usually an unlocked state is realised by connecting jumper-like points (referred to as bridges) on the CPU's surface together with a conductive material, such as pencil lead or special paint. Different CPU models require different procedures to be unlocked; usually the serial number marked on a unit belies what model it is and thus (with some research) what is required to perform the procedure.
