First, if there's a better forum to post this, please let me know.
I've currently hit a wall overclocking my i7 3770K Ivy Bridge on an Asrock Extreme 7 Gen 3 (Z68). I've stabilized with a 24hr P95 4.7ghz clock @ 1.24 vcore. Max temp is 81C cooled by an H100 in a push/pull config with AP-15 fans.
I'd like to get above 4.7ghz but even when I up the vcore to 1.35 (max I'm willing to go) I get crashes/reboots, etc. Temps aren't a concern even then as OCCT/P95 will run for about 20 mins or so and max temp is 84C. (It's my understanding that IB runs hotter than SB and thus 84C is toward the tops instead of over the top like SB).
I am really not an expert and you clearly know more than I do, but from reading about the general view is that a proper water-cooling system will do much better than the H100, as good as it is. Saying that, I dont know how high people have pushed the I7 IB's, but im guessing people have gone passed 5 ghz on a proper water system.
That's a very good overclock. I know that with the 3570k a lot of people report their wall at 4.5 and the 3770k isn't really known to go much further than that as it's essentially a 3570k with hyperthreading. Ivy bridge does run warmer than sandy but 84 is still getting up there. Reducing your temperature might result in more headroom but I'd be more than happy with 4.7. Also, how is your motherboard temperature? Those all in one liquid coolers don't do a whole lot for keeping your VRMs cool..
How high you can OC any chip is partly determined by your luck in the bin lottery.
Actually, I think you did at least better than most.
Is there some particular reason why 4.8 is so important to you compared to 4.7?
If you are in an OC competition, I can understand. But if it is for gaming or app performance, then I doubt that you will be able to detect any difference without a benchmark.
Early on, there were some tests for extreme overclocking with sandy bridge, and I presume ivy bridge.
It seem that each chip has a upper limit beyond which it just won't go, regardless of cooling.
Just luck of the draw.
Don't be greedy, enjoy what you have.
excelent video, gotta love the people posting on there that its not possible to get below ambient temps, ect, ect. its really quiet and inexpensive to do, the vacuum is causing a drop in pressure wich allows the temp to drop below ambient.