Problem with power supply, how to solve ???

Question

Iron

System:
Phenom II x4 965
rx 460
1 hdd 500gb
8 gb ram 2
PSU bars old Chieftec 600W without 80+, at 12V it gives out 450W
The last 3 days it sags to 11.5V at 12V (it sags up to 11.7 even when the browser starts)
The monitor flashes periodically, video card drivers are reset. It is not possible to play at all (In any batch, the FPS drops from 80 to 15, and after the batch it is restored). Although the aida64 stress test of the entire system runs indefinitely at constant 11.5V. Is it possible to sit on such a block without straining it too much? Can it be repaired or is it better to get a new one?
-Changed Windows, updated and rolled back firewood vidyahi all the same. The system without overclocking and overclocking does not hold at all, especially the vidyuha does not even hold the core at 25 MHz.

Answer 1

replace the electrolytes in the secondary circuit of the power supply unit (on tires +5 +12) there
they are < pcs . carefully on the mother, if some are blown up or leaking, then they are immediately visible, such changes are necessary, but if it looks normal, this is not yet an indicator that it is normal. TOTAL: in the PSU on the tires + 5v and + 12v < 4-8pcs. on mother about proca < 6 pcs.

Answer 2

Do you measure voltage with a good multimeter?
If you look at the software indicators of some kind of monitoring, do not pay attention. They can shamelessly lie and show nothing to do with real electrical characteristics.
If the multimeter shows 11.5V, this is normal and all consumers should work normally in the nominal mode. The ATX standard ( 2.01 for example (page 12) , in the other 2.x the same tolerances) allows a 5% deviation on + 12V, i.e. from 11.4V to 12.6V
Looks like overheat protection. What about temperatures under load?