Disadvantages of overclocking at stock voltages?

Hi guys

I'm thinking of doing a small overclock on my FX-8320(Maybe go for 4GHZ) without changing the voltage. But what are the disadvantages of doing this? The performance is not strictly needed (doing it for a bit of fun tbh, I'm happy with my gaming performance).

I have a CM Hyper 212 Evo cooler and an Asus M5A97 evo R2.0

None really. There is a slight increase in power consumption and heat, but the voltage contributes way more to power and heat compared to clock speed. It should be hardly noticeable.

the only disadvantage of loweer voltage is lower possible clock speed, lower voltage is always a good thing assuming it's stable

Realised I wasn't very clear. I know lower voltages are good, but what disadvantages will just upping the clock speed be?

Thanks :) Might try it out soon. 

None whatsoever, with an aftermarket cooler.

If you were on a stock cooler and you max stable overclocked without raising the voltage you might lower lifespan a little but with a decent cooler like you have you should be okay. You could have gone a little bigger with the cooler but you should be okay. 

With my 8120 I get to 4.2ghz before I have to raise the voltage and stock is like 1.31v for me. And it passes AIDA64s stability test. 

Umm... Stability?