Xtreme Addict posted a nice guide for those who want to overclock the Maximus VII Impact with liquid nitrogen. The guide mostly deals with memory overclocking and shows you how to get the most efficient memory configuration, targeted specifically at XTU. It will also help you with your insulation and general PSC tweaking.
Enjoy this nice guide in the forum!
Some of XA's tips:
1. Always boot with 100.1 MHz baseclock, Asus boards have bug and 1 per 3 boots will start with lower baseclock (99.8 MHz), even when matching frequency in OS via OC Panel/TurboV Lite), efficiency won't be good.
2. Sometimes when settings are very tight and good, frequency is okay, but still board has very bad efficiency, just ClearMOS and put everything again. I got few times "slow mode boot". Origins from Maximus VI Impact, I haven't found other fix than ClearMOS. Important: don't use saved profile when you had this issue.
3. If you get 03 code, just warm up memories and when board starts training, start pouring LN2.
4. Sometimes you have to wait 4-6 minutes until board "trains" very high or tight settins. If it trains but shutdowns at some point of traning, just let her go for few more minutes. It gives some magic.
5. For Haswell refresh use Fully Manual mode, for old Haswell, I don't recommend it.