Using the stock fan, even with a high air flow case is not recommended. The thermal design of the stock cooler is calculated to support
it at stock speed. Anything faster will draw more power. Your temperatures are high, but this means in no way that the processor is dying, just
that the fan doesn't do it's job properly.
I have that exact motherboard, but with a different processor, which means clocks will be different but the overclocking method is the same.
First thing to do is get yourself a new cooler.This involves the hassle of the installation process, but the advantage of cooler processor hence
longer life generally. I would suggest you to pick whether the Cooler Master 212 plus or the Xigmatek Gaia 1283 for good price/performance,
or for a time they have the Zalman CNPS9900ALED that is reduced of 35% if you feel like you want to
keep your CPU for a long time / overclock a bunch.
Only then I would suggest you to mess with clocks. Plus, maybe your case is due for a cleaning, so changing your cooler might lead you to
blow the dust at the same time. Take note that a good cooler still depends on the case airflow. If you only have one fan in the rear, I do not
guarantee you'll be able to push clocks very high either.