The possibility of unlocking depends not only on the model but also on the batch of produced processors. There were also batches in which more than half of processors should be unlocked, and in some batches – only several products.
To unlock it, it is necessary to have support for the Advanced Clock Calibration (ACC) technology in BIOS of your motherboard. This technology is supported by AMF chipsets with southern bridge SB750 or SB710 and also some chipsets by NVIDIA, for example GeForce 8200, GeForce 8300, nForce 720D, nForce 980.
The unlocking procedure itself is not difficult, you have only to set Auto for Advanced Clock Calibration or similar to it. You must also turn on the “Unlock CPU Core” parameter in some motherboards by MSI. In case of failure, you can try to set ACC manually by choosing experimentally a value for the “Value” parameter. A system sometimes may not boot at all after turning on the ACC, and then you have to null the CMOS content with the help of a jumper. If you could not unlock your processor, turn off the ACC and your processor will operate in its normal mode.
You can check the parameters of unlocked processor with the help of diagnostic utilities EVEREST or CPU-Z. But in order to ensure positive results, you must carry out extensive testing of your computer. Unlocking is provided on a motherboard and does not change a physical state of the computer. You can abandon unlocking at any time by turning off the ACC, and after installing of unlocked processor on another motherboard it will be locked again.