Thanks for the quick answer!
I've increased the IOH to 1.3 but it remains unstable keeping the other settings constant. It also remains unstable under a 21 multiplier with a BCLK of 181 to get to 3801MHz.
I have the Corsair H55. This keeps the OC idle temperatures at about 40-43°C, with just pre-crash temperatures at about 70-80°C.
Also, are there any recommendations about the RAM multiplier? Is it best to stick around 1600 or should I set it lower/higher?
I also read here (http://forums.tweaktown.com/gigabyte/47945-cpu-pll-effect-overclocking.html)
that it may be an idea to set the PLL voltage lower/at stock?