GTX1660ti needs only a single 8 pin connector.
A quality 450w psu like Seasonic focus can handle that.
I have no problem overprovisioning a PSU a bit. Say 20%.
It will allow for a stronger future graphics card upgrade.
It will run cooler, quieter, and more efficiently in the middle third of it's range.
A PSU will only use the wattage demanded of it, regardless of it's max capability.
The cost difference for a stronger psu is not great.
I would buy 550w. 650w if you might ever want a very strong card like a 2080.
1660ti looks to be a good value card.
Graphics card vendors bin their chips and use the better ones in factory overclocked versions
that they can sell for more. You may be able to OC more, but then again, perhaps not.
They...