Yeah 12 years is a bit long and can't imagine it'll keep chugging for more than another year or two, just get yourself a nice efficient modern PSU, and as you say 450-550 Watts is enough for people who aren't getting 3080 TI's.
I have a Be Quiet Straight Power 11, 550 Watt, 80+ Gold PSU.
But you can just grab a Corsair 80+ Bronze PSU like the CV550 if you want to spend less.







