I do not know your prices or where you might shop.
Consider a quality power supply as a long term investment.
They do not easily go obsolete.
I would look for a 750w unit.
That is enough to power any modern graphics card.
A psu will only use the power demanded of it, regardless of the max capability.
Buy only a quality unit, tier 1/2 on a list such as this:
Credit to @Starelementpokeand @Energycore for helping out with this long-awaited refresh of the old PSU tier list by Aniallation (who previously went several months without logging in), leaving the old list in need of help. This is simply an update of the list that was flawed in creation by the P...
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I like the Seasonic focus units with 7 or 10 year warranties.