Summer is in full swing and its hot. Your system is taking the brunt even when properly cooled will suffer. I suggest when things get hot, open case, place a 6in. fan to blow into case. Your system maybe working great but overall the stress during summer months can take its toll. Even if your room is A/C'ed it works better with a simple fan.
The small fan is AC powered, reduces any system power strain. It's usually quiet and its airflow is far better than a 120mm one, even when mounted on the side. Of course you can replace it a with a much larger fan to help better. Once the summer heat period is over, remove and store. You can use the "clamp type" as well.
This one tip will help you sleep better tonight
A few seconds are all you need to get a better night's rest.