changed PSU and now case fans stay running when pc's off

[FNP90]

I have switched from a PC power and cooling to a EVGA PSU and now when I turn off my computer the case fans stay running. I put the old PSU back in and the fans power down when the computers off. With the EVGA the CPU fan and everything else powers down like normal but the molex connections always have power and that's what I have my case fans powered by. is there something i'm missing or does this mean something is wrong with the PSU?

The EVGA is a 120-G1-1000-VR
and my old PSU is a PPCMK3S400

 

[VirtualLarry]

bizarre

 

[Deders]

Some PSU's and Bios' do have a feature that leaves fans going for a while after powering down but as these are from the molex connectors which aren't exclusive to fans I would say it's a fault with the PSU.