Yes make sure it's the K version. This is critical!
As for PSU. If it's a good manufacturer and PSU isn't old - 550W will be enough.
New GeForces are very tame when it comes to power consumption so you will be fine.
HardOCP uses overclocked-to-hell PCs to test videocards and they also test power consumption
That's the full system load, not just videocard load.
So don't believe people who say you need from 700W and to infinity
As for PSU. If it's a good manufacturer and PSU isn't old - 550W will be enough.
New GeForces are very tame when it comes to power consumption so you will be fine.
HardOCP uses overclocked-to-hell PCs to test videocards and they also test power consumption
That's the full system load, not just videocard load.
So don't believe people who say you need from 700W and to infinity