Overclocking can have it's pros and cons, however I'm not an OC expert by any means and usually leave it up to the motherboard tweaking software that comes with the motherboard.

Pro:

CPU intensive items will see a large boost in performance, stuff like data compression, cpu based video conversion software, distributed computing like Folding AT Home will all see boosts in performance.

Cons:

Increased heat output from the CPU and any other component you've OCd requiring additional cooling

Increased power draw

Possibility of introducing corrupted data if the OC is not stable.

Many games will not see a noticeable performance increase when overclocking

Note:  I have found the Thermal Interface Material (TIM) within Intel CPUs is absolute garbage especially when pushing the CPU limits.  To get around this issue you typically need to De-Lid your processor and replace the TIM with a better TIM such as Thermal Grizzly Conductonaut or another variant of a liquid metal TIM.

Note 2:  Using the Liquid metal TIM can be very dangerous to your components if not installed correctly.

Note 3:  De-lidding & in most cases just the act of overclocking will void warranties so do so at your own risk.

Note 4:  By replacing the stock Intel TIM between the core and heat spreader the average per core temp dropped by 18c at stock speeds 

However yes with a Corsair H115i cooling an Intel i7-8700K I'm currently running max speeds of about 5.22ghz with the CPU usually bouncing between upper 3-4Ghz doing general desktop work

Great information! Ill just leave it where it is.

I am not sure if my faster turn times in GC3 and Civ6 are due to fast 6 core 12 thread cpu or due to having 32 gigs of ddr4 ram..

Between Delidding my processor and replacing the TIM with liquid metal and using a Corsair H115i "Dual 140MM fan AIO water cooler" my max temps are around 75C after hours of 100% cpu utilization running at about 5.22ghz.

@Larsenex if you don't mind voiding your CPU warranty, replacing the TIM is a good way to significantly drop the core temps possibly increasing the CPU longevity unless the CPU gets damaged during the delidding or the liquid metal gets applied improperly, also replacing the thermal compound between the CPU heat spreader and your heatsink with a better compound is a good way to drop temps a few more degrees compared to stock thermal material slathered on heatsinks in the factory.

Note:  Liquid metal thermal material has gallium in it which will destroy aluminum, so if you're using a heatsink with an aluminum plate or an alloy with aluminum in it, so you will have a bad time if you try to use one.