The advantage of an unlocked processor is that you get fine-grained control over the clock multiplier.
The clock multiplier is only one of several variables adjusted when practicing the art of over clocking. Years ago, before CPU manufactures locked multipliers, malicious people would buy cheaper clocked CPUs, change the multiplier and sell the computers as faster models. To prevent this, manufactures made it harder to overclock by locking the multiplier.
CPUs with unlocked multipliers are primarilly targeted towards people doing extreme over-clocking, (like with liquid nitrogen). You will be spending 10% more money for 1-5% more performance.
tl;dr You most likely will be better off spending that money on a better hard drive, than the marginal increases those CPUs will give you.