I was pretty sure from way-back-when that the Asrock was a fairly good board.
If you're running your system at load 24/7, I'm guessing you could do 4.4 or 4.5 and maybe keep the load VCORE under 1.30 to 1.32V. In fact, I'm more optimistic. I pretty much thought the i5 was as OC'able as the i7. I just consulted my notes from summer 2011, and those voltages reflect multipliers of 44 and 45 with bCLK set at 103!! I was already running over 4.6 with those tests.
I left off bumping the bCLCK and set it at 100, starting with the voltages I got from the earlier tests and backing them down. I think 44 and "4.4" is possible -- maybe below 1.30V load.
But it's your own sense of safety that counts. I have EIST enabled at 4.7, and I wouldn't run the system that fast for 24/7 loading.
Still . . . . some here -- IDontCare among them -- think the SB cores were still "safe" at higher voltages. We thought 1.35V was the upper bound of "safe;" a lot of people said "Oh, 1.40V is OK." It just seems to me you won't hurt anything if your load voltage is 1.30 or lower for that processor.
But it also depends on the processor itself . .