Measuring the 12 volt line on old PC power supply

I am using an old PC power supply for powering the monitor and other 12 volt things on a computer in stead of the usual wall-warts . I measured the 12 volt line and it was pretty low - actually a little below 11 volts . I figured it was bad so I dug others out of the junk box and found that all measured way below 12 VDC .

Any of you use these cheap supplies ? Have you ever measured the output voltages ? I just can't believe that all meters are bad or that all my old pc supplies have gone bad. Is it possible that this is a normal condition on the gillions of computers out there ? 

I just connected a small auto tail light bulb to the 12 volt line on a 250 watt unit which is labeled to deliver 10 amps of 12 volts and the measured voltage dropped from 11.35 to 10.56 volts while drawing way less than 3 amps. Anyone here ever checked these ? 

The way these power supplies work, the 5V or 3.3V line is regulated and the 12V line just comes out near 12V due to the relative number of windings. Put an automotive 12V taillight bulb on the 5V line, now measure the 12V line. There are mods online to shift regulation to the 12V output and get even more power out of it. They are not for those who are not already fairly experienced.

I'm learning things I never knew about - right now I'm placing smaller and larger wattage bulbs on the 5 volt line and the 12 volt line while measuring the 12 volt line - trying to see if anything keeps the voltage at 12 or above - nothing so far.

At your mentioning that online mods can be found that regulate and allow increased current , I'm googling around in search of what I want - maybe even adding variable voltage. Actually I do almost what I want to do now using a variac and a diode bridge . This idea of using some of my old computer supplies seemed like a good possibility to replace that un-handy setup.