Dual PSU setup - PSU switches off

[Almondo]

Using a coolermaster stacker with PSU's. Only recently am i finding that one of the PSU's (the one powering the HD, Optical devices and fans) just swicthes off (generally whilst playing games, which i do alot). What could be the problem here?

[Electron Chaser]

I need more info on how your dual PSUs are wired, what is each of them powering be very specific please. Also Brand,model, and rails of both the PSUs.