Originally Posted by tazmizzaz
I'm currently running 18 HDDs on my 4+4 U setup. With 2 CPUs, 32 Gbs RAM, 6 SATA cards, most of the same old components and I run a peak boot load of 380 Watts and an average run load of around 250-300. That does include a KVM, plugged in but off monitor, Network switch and a few other small items plugged into my UPS.
So based on my experience I would say that 350 is likely doable but I would caution that most PSUs stop functioning correctly once taxed beyond 75% of total (assuming they are really good quality and handle 75% well). At 75% you only have 260 Watts to play with and that is very likely to be cutting it close with 12 HDDs and a random assortment of Mobo, CPU, etc. It might be practical to build computers that take less than 50W at full run but those systems don't typically have the ability to handle even the minimal requirements of 12+ HDDs.
cold boot is the key:)... peak boot is not matter.
Cold boot-> "Starting the computer by turning power on. Turning power off and then back on again" grab from the net.
as I stressed on my posting: test on cold boot many times...
I would say 80% is pretty solid number
the issues that I know when PSU is getting closed to the peak
1) ripple noise
2) drop voltage (mostly on 12V line )
3)voltage spike/swing( this would cause some damage, supposely swinging from 12V-9V-12V in the matter of seconds)
I would pick a safe way: 500W is the border line..
if someone need to have fun with 300W-350W, buy a good PSU!!!
an example on my lga775 system:
I reuse my 1U supermicro E6XXX 65W CPU with an pci-x 6 ports nic, 320G HD, and 8G RAM for running esxi5 (firewall, some vms for monitoring). it shoot to 120W during the coldboot... and drop to 80W... and would move to 100W * when some VMs are running cpu intensive program*.
the supermicro PSU is 260W....