I have a Antec 650 watt PSU. It lists the input as 100-240 volts at 10 amps. All I know is volts x amps = watts. With this formula I figure I need a 1200 watt UPS. 120 volts x 10 amps. A 1200 watt UPS is quite expensive and large for my computer. I can't imagine my computer pulling 10 amps. What is truely needed for a 650 watt PSU?
Figure out what your PC is pulling (use a PSU calculator), and allow some headroom. Consider anything else you plug into it, like your monitor, cable modem, and router. Don't even think about plugging a laser printer into a UPS smaller than 3kVA. My .sig rig + monitor pulls <200W from my UPS. I chose that size to get a little more run time. Ymmv.
I run an APC ups of 750 wts. Mainly its because it give me some time to get everything such down in case of power outages or brownouts, which happen fairly often where I live. A 650 wt is probably good enough. My main uses for a ups is to give a steady rate of power to the psu without the wide variations that come from the wall socket, and as mentioned before, to give time for orderly shutdowns when the power fails completely.
Thanks for the advice.
My system is;
Patriot 800mhz 2 x 1ghz
Intel 840 Extreme Edition 3.2 (OC'ed to 3.4 in BIOS, Vista reports 3.83)
3 WD 10k Raptor hard drives in a RAID 5 config.
Sapphire/ATI X1600 video 256mb
56k PCI USR modem
1 120mm fan + 2 80mm fans in case
MS USB wireless mouse
plug my camera into USB sometimes
The closest PSU calculator I have found puts me at 475 watts but it doesn't match my rig exactly. Gigabyte says not to use the GA-965P-DQ6 m/board with under 400-450 watt PSU.
So I got my Antec 650 watt Trio TruePower PSU. I figure I have a little head room. If it's got 650 watts output after AC is converted to DC I don't think matching the output to input is accurate and therein lies my question. Antec states on thier spec sheet it needs 100-240 volts at 10 amps.
I have e-mailed every tech support line I can find at UPS companies and got nothing.