As far as I am aware the Pi 3's CPU is currently not overclockable, its maximum clock speed is set at 1.2GHz.
But what about overclocking the GPU? Is it even possible? And would I see performance gains in applications like playing games?
Raspberry Pi Stack Exchange is a question and answer site for users and developers of hardware and software for Raspberry Pi. It only takes a minute to sign up.Sign up to join this community
Yes it is possible to overclock the GPU and yes , this leads to a performance improvement.
Look at following resources:
Please don't forget that overclocking is a gamble , your Pi might not be overclockable , crash and corrupt SD cards.
Active cooling is highly advisable while overclocking the Pi3 :