Well from what I was reading about, it seems like the 8-pin is used for extra capacity that was at first needed only by servers. It seems that the 8-pin will help regulate power to ALL VRM's on a board more efficiently or maybe at all. Where 4-pin may be limited to using say half the VRM's or not as efficiently on all VRM's. It does seem that the 4-pin wattage limitation is around 192W and 16-22A depending on a few variables.
There was an article I was reading that information from here:
http://www.tomshardware.com/reviews/power-supply-specifications-atx-reference,3061-9.html
If you're stable, and not overheating, and that board is capable of handling the load with 4-pin I see no major issues at least initially. I have OC'd on 4-pin boards just fine before, but not a 3770k at 4.5ghz.
A little more google searching led me to this article that states this particular 3770k at 4.4GHz was only using 140W, but jumped up to 236W at 4.9GHz @ 1.35v.
http://techreport.com/review/22833/...ore-i7-3770k-overclocked-on-four-motherboards
Honestly, I think most people aren't bothered too much by it...if you're going for much more, one would assume you'd want to buy a board that has the power input and VRM's to support consistent voltage without burning up. Your VRM's may become hotter under load because of the power limitation of the 4-pin connection. Your board seems to rate pretty well and Gigabyte builds decent products as well (overall at least imho from my experience). I would say if all is stable, temps are good, and power fluctuations aren't an issue, I would not be too concerned with it.
Maybe someone will come in with a better answer, but in short I would say to not go too much further with your OC because it may overburden the cpu power circuitry, though I am not sure if your current OC is pushing the limit or not. But there are ways to do the math, and/or buying a Kill-A-Watt in-line power adapter to read the consumption from the wall too. I hope that helps a little bit.