Water Cooled IS It Safe To Use Sleep Mode On Powerful Water Cooled Gaming?

IS it safe to use sleep mode on powerful water cooled gaming? - water cooled

I have my own built PC Digital Storm.
He has cooled 3 and GTX 280 graphics card every two Intel QX9775

The team is very strong in my mind and left the power for the whole day and I just wanted to know whether it is safe to use sleep mode for this kind of PC.
And sometimes it is awakened from sleep by itself after a few minutes away from my touch with the mouse or something, everyone knows what can cause this problem.