Global Conflict

There are so many different calculators out there, I just tested a few, Asus own calculator recommended you to have at least 800W PSU while that page that was posted here before said 550W.
Anyway, I wouldn't recommend buying anything under 700W if you're gonna run SLI or Crossfire.
Even it your 650W can handle it, it's better to have a larger one because it will never be under heavy load and develop heat in your case.

so... next time you buy a motherboard, you'll need to buy new memory.
the next gen DDR4 memory
see that key notch? thats going to stop you from inserting DDR3 into a DDR4 bank (and the fact its electrically incompatible)

Doesn't the PS4 use DDR5?

The PS4 uses GDDR5, the same kind of memory that non-shitty graphics cards use.

Most of the power supply calculators out there are complete crap when it comes to giving you an honest unadulterated answer on how much power you actually need. Some calculate the wattage your rig might consume, others give power supply unit recommendations. Some calculate their numbers using TDP values alone. Some purposely inflate their numbers so they can sell their own products. The point is, you can't really take any of the so-called calculators out there seriously unless you know how they came up with their number. My figures all came from empirical testing from Anandtech and TechPowerUp, and are adjusted for rectification efficiencies and buffers.