HaHa!! ''450 WATTS''! 12Vx18A + -12Vx0.5A + 5Vx30A + 3.3Vx21A + +5VSBx1.5A = 448.8W!! That reminds me of another '90s spec - PMPO speaker ratings!! The ''power input'' they could sustain for 1 nanosecond,
BEFORE a Chernobyl-like MeLtDoWn!!
Back to the problem...I think the
ONLY THING that can account for the longevity of this PSU, is that it probably operated @230VAC in a 60W budget/basic system it's whole life! Would have kept the current input and therefore the stress and heat much lower than the North American 115VAC!!
NOW, for the solution...You want a PSU with a
MINIMUM TRUE 450W output on the 12V rail(s). Which is how the
QUALITY MANUFACTURERS spec their PSUs, now. The 12V rail is what primarily powers your Motherboard/CPU, and solely powers a GPU. For longevity, quality and the least power loss without breaking the bank, I recommend a name brand 80+ Gold PSU, such as Seasonic, EVGA, Corsair, Cooler Master, etc.
Some reasonably priced examples are :
Seasonic X-Series (550W-850W) and G-Series (450W-750W) were pretty good;
EVGA G2/G3 (550W-and-up);
EVGA GS (550W-and-up)
EVGA GQ (650W-and-up);
Corsair HX and AX-Series (Seasonic based PSUs);
Cooler Master RS and V-Series (depending on the manufacturer).
Some of the above PSUs have been discontinued/replaced, but you might be able to track down a good, used one within your budget. If you
REALLY want to know who manufactures what, visit here :
http://www.realhardtechx.com/index_archivos/PSUReviewDatabase.html
(by no means a
COMPLETE LIST, but includes reviews and ratings, so pretty good!)
You'll have to do some local research to determine the availability and best price/value/quality for your needs, but a
TRUE 450W MINIMUM PSU! Good Luck!