I have this old PSU from an old computer and I noticed that the 5v output is a reasonable 11A. That got me thinking (dangerous, I know) - I wonder if I can run a flashgun from this. I have an old Nikon flash that I'd converted to run off AAs (it previously used an oscure, expensive type) so it was easy to connect to the 5v output( The red&black wires on the molex plug). I removed all the excess wires that normally plug into the motherboard, leaving the grey & green wires which are the on/off control wires. These I connected to an old switch (from a vacuum cleaner) and fitted it neatly next the power socket on the back (see arrow on the photo).
It works fantastically, and considering that particular flash only pops at full power when used off-camera, the recycle time is phenomenal. I was getting about 4-5 pops per second ON FULL POWER. I stopped counting when I got to 30.
My next thought is whether it's powerful enough to power 2 flashes. I may try it sometime. Obviously it's no use for shooting out & about, but perfect for studio work!