You'll significantly lower its lifetime with electrical migration I'd say, with 45nm Intel chips that have a spec of 1.365V it is widely accepted that 1.40V is the max and with the 65nm chips 1.50V was the widely accepted norm for 24/7 with air cooling.
I honestly don't know with AMD chips, perhaps you should make a thread and ask the others on here.
EDIT: I've asked the question on another overclocking forum, will let you know the answers.
EDIT: Hey Joga, got a reply from another forum, it appears I may have been correct about your 1.6V
Originally Posted by mAJORD
1.5 is OK, but you'll see little gain over 1.45v..
Aim for 3.2 to 3.3 on GOOD air for an avg chip and the 1.4-1.45v range