That's an excellent overclock for a Haswell CPU. What cache ratio ? Manual or Adaptive voltage control ?
My goal was 46 CPU Multiplier and 46 cache ratio which I was able to do at 74C on Asus BIOS 0804 w/ 1.375 VID ....hadda go 46/43 (more than 3 difference results in performance impacts on things like image editing) on 1102 ..... mighta been caused by BIOS or memory issue but needed more voltage at 46/46 and didn't wanna go that high. In my memtest redo, one module no longer passing and waiting for replacement. Just installed 1402 and will try again when new sticks arrive.
What are you using to determine stability ? For some, making it into Windows and a CPU-Z verification is considered "stable". If I can run RoG Real Bench for coupla hours with max temps under 75C and max voltage under 1.4v (Voltage spikes during Open CL portion where AVX instructions are present), I consider that reasonably stable tho I have run into conditions that have RoG RB stability but crap out in certain games ..... 1 spot in Metro 2033 is a problem and BF4 has been problematic but getting better with each patch.
Still others won't say the system is stable till it runs P95 w/ AVX instructions for 8+ hours. Be careful if you try this under adaptive control as voltage spikes from the AVX instructions can be dangerous.
I find voltage more than heat to be the limiting factor on Haswell OCs.... great Haswell OC thread over on OCN....gotta be 2000 pages long by now.
Giving the variability of the CPU lottery, my cooling / voltage recommendation is as follows:
1.15 - 1.20V - Decent budget cooler like Hyper 212 (4.3 GHz)
1.21V-1.25V - Phanteks PH-TC14-PE, Thermalright Silver Arrow, Noctua DH-14 .... 240/280 radiator @ 1500 rpm or 120/140 radiator @ 2600 rpm AIO (4.4 - 4.5 Ghz)
1.26V-1.30V dual radiator (240/280) custom water cooling solutions in push / pull (4.5 - 4.6 Ghz)
1.31 - 1.375 custom water cooling solutions multiple rads (4.6 and up)
Of course if ya get a great chip ya can do much better, and if ya get a particularly bad one, the above won't cut it.
You can avoid voltage spikes by running in manual mode at fixed voltages. I prefer the advantage of Adaptive Mode which currently has my CPU drawing only 8.7 watts. When AVX instructions present, expect a 0.1 or more voltage increase under Adaptive.