T5810 - CPU changed e5 1630v3 to 1650v3 current/EDP limit limiting clock boost

I have a T5810 that had an e5 1630v3 CPU. I have just replaced this with an e5 1650v3 which is a like for like requirements wise according to all my research.

I have used Intel XTU and I know that Dells lock everything down so can't use it to change anything but as a monitor tool its showing "Current/EDP Limit throttling" and the voltage max I get is 1.169V instead of the 1.3V that the CPU should be able to get to. It limits my CPU boost to 3.59GHz when it should go to 3.8Ghz.

I know the TDP is 140W for both and the sockets are compatible so I'm not sure why there is now a current limit in place?

Any help would be much appreciated.

Thanks