I bought a VX550W Corsair PSU to replace what seems to be a dying (i.e. intermittent freeze and restarts) Allied Model: AL B450E PSU on an old K7 Triton 400 Series Mobo. With the new VX550W Corsair PSU the system will POST and then will usually reach the windows logon screen but rarely any farther (sometimes desktop for a few minutes) in the boot process. So I tried the old, but seemingly bad, PSU and it will act as usual (PC usable, sometimes for days, but intermittent freezes and shutdowns). So with the new VX550W Corsair PSU the only difference is the system shuts down unexpectedly more consistently (usable for only minutes instead of usable for days with the old PSU). The only thing I can find on this is that the newer PSU might have a minimum amp drawing requirement on one or all of the three rails. Also, the old PSU does have a -5V rail and the new one does not (ATX12V Ver 1.3 revision I believe) but it seems this -5v rail was used for ISA boards and is no longer needed because PCI does not require it, at least that's what I have been told. Any help on whether or not the new PSU is combatible with my old motherboard would be appreciated.