750W PSU for a 1080TI and a 1440p, 144hz G-sync monitor?

[hector.mtzm6]

I'm about to replace my computer and I already got some parts. And I recently bought a 1440p,144hz monitor. The thing is that my current computer is rebooting every time I play in 1440p ,144hz without the 1080TI installed. The first thing that came to my mind is that the PSU is not providing enough power. The current PSU is a Corsair TX850, 80 bronze plus.
is my current PSU failing, or it is too much for it?

Current computer:
CPU: AMD FX-8350
MB: Asus Crosshair V Formula-z
GPU: Asus GTX780TI-DC2OC
RAM: 2x8 Trident ddr3
Cooler: Corsair h100i

I bought a Evga Supernova 750W g3 80+ gold. Now I don't know if it is enough for the new computer.

CPU: Ryzen 7 - 1700 (With overclock)
MB: Asus crosshair VI hero
GPU: Asus strix 1080ti
Cooler: Corsair h110i
Ram: 2x8 ddr4 G.skill Flare X.
And of course the 1440p, 144hz monitor.

Thank you for the help.

 

[madmatt30]

A g3 750 is more than enough by around 300w.

 

[hector.mtzm6]

A g3 750 is more than enough by around 300w.

Thanks for the quick response.
So.. We can say that my current PSU is not working correctly?

Edit: I checked the temperatures of the CPU and the GPU and although the GPU temperatures were around 70-80 degrees, it appeared to be the problem. after I put the fans at 85% it stopped rebooting.