The I5 6600k is limited to a maximum speed of 4.6 GHz.
The I5 6600k is limited to a maximum speed of 4.6 GHz.
I need to admit I didn't reach 1.4V, possibly because I didn't add enough... But honestly, I might just stop here.
It's not the motherboard, it's not the cooling, maybe your power supply isn't strong enough (not enough watts). But I believe the main issue is that 4.6gh is quite high and your PC has hit its stability limit—it can't go any higher. No matter the reason, the clock speed is already very low for most tasks (gaming, editing, etc.), so you probably don't need more. If you're an overclocking fanatic and want to push your CPU's limits, it might be the best you can do.