Well, if you find that your system runs fine, then it should be OK.
If you find that your system restarts suddenly when you strain the power supply (for instance, if it takes several goes to get it to start from cold, if it crashes/restarts during Prime 95, F@H, Sisoft Burn-in, or gaming, or if it restarts when your CD drives are trying to spin up a cd).
If the system DOES restart without warning when stressed, and your voltages are low, then you know where the trouble is.
ImG