Complex sentence: AMD CPUs are generally unlocked by connecting bridges (jumper-like points) on the top of the CPU with conductive paint or pencil lead, but different CPU models (determinable from CPU serial numbers) require different procedures to be unlocked.
Split into simpler sentences: AMD CPUs are generally unlocked by connecting bridges (jumper-like points) on the top of the CPU with conductive paint or pencil lead. Other CPU models (determinable by serial number) require different procedures to be unlocked.