Like the other posters above said, "11. - 11.2 volts is out of tolerance." But is is probably worse than you think. Remember, a PSU tester puts a minimal load on a PSU.
Borrow a meter and check between the yellow and black wire on a drive molex power connector while the PSU is running.
With a little over 11 volts, a good PSU would not have let you boot.