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UCS C420-M3 PCIe Slot Power Maximum Wattage


I am trying to install a Fusion ioMemory SX350 card into a C420-M3 running BIOS v1.5(9)a.  The PCIe card works, but it's operating at the default power of 24.75W, and the documentation indicates that it can provide better performance if it can use up to 75W.  I have the ioMemory command to have the card increase the power, but the documentation indicates that this could cause damage to the server if it can't support it.  Thus, I want to confirm things before making such changes.

The ioMemory SX350 is installed in a vSphere server, and the VMKernel.Log file indicates that the C420 isn't reporting back how much power the slot can provide.  Here's the log entries:


vmkernel.log:2019-03-05T21:23:28.905Z cpu27:66483)<6>fioinf ioDrive 0000:43:00.0: PCIe Slot reported power limit: 0mWatts
vmkernel.log:2019-03-05T21:23:28.905Z cpu27:66483)<6>fioinf ioDrive 0000:43:00.0: Warning! PCIe Slot reported power 0mWatts is less than product minimum power 13000mWatts
vmkernel.log:2019-03-05T21:23:28.905Z cpu27:66483)<6>fioinf ioDrive 0000:43:00.0: PCIe Adapter power limit: 25000mWatts
vmkernel.log:2019-03-05T21:23:28.905Z cpu27:66483)<6>fioinf ioDrive 0000:43:00.0: PCIe Adapter power Throttle point: 24750mWatts


I've looked at every C420-M3 document I can find, but nowhere does it indicates the maximum power provided by a PCIe slot, and at power-up, as you can see above, it indicates the power limit is 0mW.  The card is installed in Slot 7.

If someone can please indicate the maximum PCIe slot power supported on a C420-M3, I'd sincerely appreciate it.

Thank you,


1 Reply 1

Kirk J
Cisco Employee
Cisco Employee


I believe I had a similar case about 5 years ago, where a customer was trying to override the 25Watt cap these have on the C420M3 PCI-E slots, and torched the Fusion 2 io Duo.

I believe the C420M3 supplies less than other servers (i.e. C240m3/m4) for the PCI-E power.

I would highly advise against trying to override the 25watt/25,000mwatt limit.





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