LoWRiDeRz
To be honest no matter what I try I've never seen it pull 450w or close to it. Highest I've seen were blips of 430w but it isn't maintained despite temps being just 70c. Possibly the card requires much lower temps / exotic cooling to get the most out of the xoc bios
Your going to need to keep the Card much cooler ... 50 to 53 C to see max anything
Nvidia Boost control will cut back the GPU above 53C
The other thing is the software load needs to need (pull) that much power ... software load & monitor resolution matter