Yep, AMD does the same with current limits. 110A for K10 AM2+ and AM3 cores and 20A to the IMC. This is the peak limit.

Not sure if any OCP trigger is activated which causes CB... if it did, why would it occur on some and not other CPUs?
And why would it occur at a low current?
It depends on what the values for VID registers are, different P-States enable a different current to the core and IMC AFAIK.