Got a factory 3570k with a big ass Hyper 212+ sitting on top of it.
What are some safe overclocks for the 3570k? I'm looking to hit at least 4ghz, my case has about four fans in it and average temp is in the 31c's and I haven't tested it under load yet.
ASUS Extreme4 Z77
8gb DDR3 Ripjaws
Sapphire Radeon 7850 (not in yet)
You'll be able to get to 4Ghz just fine, and yes, 31C is just fine for idle, as well. I'd say you should be able to get to 4.2-4.3 without much issue and possibly 4.5, if you're willing to run it warm.
Undervolting is a GOOD thing if you can do it because it'll run cooler (always a good thing for Ivy CPU's). No harm in it at all, other than instability, but that's not actually damaging.
Overvolting causes MORE heat and slightly shortens the life of the CPU, increasing more the more voltage you use, but from what I've seen, that won't really be a problem anyway, since Ivy CPU's don't really like adding more voltage because they get too warm.
So, as I said, just try undervolting or see what you can do at stock voltage.