Max 88C while under 100% load? Thats kinda high.. Try lowering the voltage, because Voltage is the main factor of heat, so try 1.3 at 4.5, if its stable, keep it, these newer Intel cpus get HOT, and all you have is an air cooler, but its a decent air cooler. Anything over 80 for a long period of time is BAD, but you are running at 100% load, so try and get it to 80 under 100% load, or at least 82, because 88 isnt bad bad but still ehh. If you want ultra safe make sure its below like 75.