Hello Paul.
Why is it not as simple as reducing the voltage on the vcore?
Try dropping vcore by one increment at a time, use the minus key on your keyboard while in bios. Then do your stability test and see how it goes.
Folks over complicate things way to much, just because there is a bios option in the voltage section, or any other section for that matter does not mean there is any need to change it.
Your system is running nearly exactly the same as mine TDP wise at stock by the way.
To help us help you - please provide as much information about your system and the problem as possible.