Optiplex 790 Power supply; can I use this Corsair RM550X model?

I have this power supply:

CORSAIR RMx Series RM550X 550W 80 PLUS GOLD Haswell Ready Full Modular ATX12V & EPS12V SLI and Crossfire Ready Power Supply.

I bought it at newegg: https://www.newegg.com/corsair-rmx-series-rm550x-550w/p/N82E16817139144?Item=N82E16817139144

I always keep a spare PS for my computers, and this PS is currently in another (even older) machine. I'd like to know if it can be transferred to my Dell 790MT if need be.

Will it physically fit into the dell tower, and will it work at least as well as the original supply which I'm still using ?

Thanks guys.