650W would be enough if rest of the parts are at stock.
Question is about quality of particular PSU and its components.
And Silverstone is mostly toward parts chosen for cheap price.
That wattage and age hints to it belonging to that cheaper parts group.
Even their latest 80+ Titaniums aren't any high end PSUs, with ATX spec breaking bad ripple and failing hold up time.
And certainly if you can afford such ludicrously overpriced graphics card, which won't hold value for many years, buying quality PSU with decade operating life shouldn't be too much.