PSU limiting power?

[CbrosTheDude]

Hello,

I had a relatively stable build using a 7700k at 4.8GHz and a GTX 1080 at 2GHz core clock, powered by a Corsair TX650M 650W PSU.

I recently replaced the GTX 1080 with a GTX 1080Ti, which worked like a charm. I started overcklocking it untill it crashed Furmark (and not the whole system like the previous card). A monitoring app displayed 110% power usage when clocked at 1.8GHz and 71°C. Later, I noticed fps slowly dropping in games and power usage dropping as well under 75% when GPU usage was still at 99%. Another Furmark test confirmed the GPU wouldn't go over 80% of its rated power while under 63°C and synthetic load.

Can it be that my power supply is not powerful enough to overclock the card + CPU? Why would the slow down only occur after wome time then?(30 min)

 

Thank you for answers

[TheBean]

if you overclock, power starts rising *fast*. if you really want to oc that gpu, try undervolt the CPU and ram. 

[BMorgan922]

That power supply should be fine. Even with both overclocked and under synthetic load it should only draw at most ~400w. Try going to Nvidia control panel--Manage 3d settings--Power Management mode--Prefer Maximum performance.

[CbrosTheDude]

I tried undervolting the CPU and RAM, and even downclocking the GPU, checked the Nvidia control pannel but nothing I can do. Once it has slowed down, it does not go above 51% GPU power in Furmark even when GPU usage is at 100% and all th power seems available.