When is too much voltage too much on a PC?

Solution 1:

Your voltages are OK according to the ATX 2.2 standard, where voltage tolerances for all rails except -12 V and -5 V are ± 5%. For those two negative voltages, the tolerance is ± 10%.

Here is the table for ATX voltage tolerances

So these tolerances are recommended, and if your system is out of these tolerances, it doesn't automatically mean that your computer components will die. Actually, I have seen systems that were worked for a long time with a power supply that is out of allowed tolerances. Although, this depends significantly on components used in manufacturing of the motherboard.

The more important thing for you would be to check your 19 V DC supply for quality of the output voltage, meaning that your 19 V DC voltage is maybe not filtered well, and thus introducing the noise to your motherboard which is much more dangerous. Just put your 19 V brick on an oscilloscope and check that you have the real DC voltage without any significant noise.