Maximum Power Usage on example system

[mivanov93]

What's the maximum power usage for a system composed of:

Intel E3-1245V3
4x8GB ECC 1600Mhz
Sapphire 6950 2GB
3x Nvidia GT 630
(by the way: is it bad for the motherboard to leech that much power of it? since those 630's are powered from x1 PCI_E slots)?
1xA-data SSD 120 GB
3xWD 2 TB Black

I am looking to get a UPS so I need to know the maximum power draw on full load. Will 600W be enough? Or perhaps 900W is more like it? I don't need to run it for a long time on the UPS, just to be able to close and save everything and do a graceful shutdown - that is less than 5 minutes.

 

[mindless1]

Are you listing 600W as the sustainable output or is it really the VA (volt amp) rating which is usually a little under twice as high as the wattage rating?

600W sustainable output is overkill but marginally acceptable for the VA rating on a typical UPS (if honestly rated). I'd spend the extra money for a 800VA to 1000VA instead. The less you run down the batteries the longer they will last, and I'm guessing with 4 video cards that you probably want at least one monitor to also be powered.

If the motherboard is competently designed it should be able to supply full rated power to all the PCIe slots simultaneously. The only way to know that is place trust in the manufacturer or test it yourself and use a multimeter's probes strategically placed on the video card at power supply contacts and see how much voltage droop is happening at full load compared to measurement at the PSU connector while the system is in the same state. It's going to droop some but should only be around a couple tenths of a volt difference at most (staying in ATX specs).

The lazier way to check would be that if it works and there's no smoke you're good. Generally if a video card doesn't get enough voltage it'll downclock or have errors.