MSI Gaming GTX 970 Overclocking

[EasternGamer]

Hey there, I have a GeForce GTX 970 GAMING 4G edition from MSI. I overclock it to what I would call 'extreme'. I have the memory clock at 4007 MHz(4 GHz) and the core clock at 1507 MHz(1.5 GHz)
The core voltage(+87mV) and power limit(110%) is set to as high as they can go with MSI Afterburner.
However the temperature doesn't reach over 70~C. Is it safe?
With the GPU fan on full it can reach only 62~C and nothing above that. I would also like to know whats the optimal performance temperature for this GPU.

 

[ihog]

Those temps are pretty optimal and definitely safe.

 

[EasternGamer]

Those temps are pretty optimal and definitely safe.

Thanks. So basically as long as the driver doesn't crash, you don't get any extreme artifacts and your temperature isn't extreme is that safe?