Computer hangs due to underpowered UPS?
I just bought a new UPS. Now since I started using it I experienced at least 3 random freeze in Windows 7 and it happens during the first 10 minutes of start-up. Note when I say freeze, I mean I literally can't do anything in Windows, everything is frozen including the mouse cursor.
Is it possible that I bought a broken or underpowered UPS? Can an underpowered UPS make a computer freeze?
BTW, this power calculator says I'm under 300W, but I do have 500W PSU.
Update: FEB 9, 2012
I have replaced my APC UPS with another brand: FSP UPS which is the same brand with my PSU. It's been running with no problem for the last 5 days.
In reference to my answer below: Could it be really true that non-SmartUPS APC models are not compatible with active PFC PSUs? I find it hard to believe since most branded PSUs are active PFC.
Initial Complaint Computer freezing on startup, after connecting to UPS:
Yes, when your computer is starting up, it pulls more power initially to load up everything, which can cause an excessive drain on a UPS that isn't slated to handle the peak power consumption of your computer, hence the freezing.
UPS Recommendation and Breakdown Given that you have a 500W PSU in your system, and you probably have your computer, monitor, printer, cable modem/router/dsl modem, scanner (if you have one), and you probably have external speakers for your computer, you are looking at most likely a peak performance of 600Watts. Thus, you are probably looking for a 750Watt UPS, not the 500watt one.
After returning the item to where I bought it, we are unable to figure the problem until I contacted APC support:
APC support said my PSU is incompatible with my UPS. Moreover they said, any PSU with Active PFC (Power Factor Correction) is not compatible with my UPS. So the solution is to get a PSU that is none PFC or get a compatible UPS (usually APC Smart UPS however it is 8x more expensive).
When we first bought UPS items we got the cheap ones. They were just enough power, they were "unregulated" for these it meant that the power had to take a good dive before they would switch. It was not long before we realised that they had zero value. I could test them by pulling the plug , but lazy brown-outs (vrses black-outs) would still knock the computer up. After that we got overrated, and fully regulated "brand name" ones, and have not had any of the problems we had with the cheap ones. I couldnt even sell them to anyone, because of how useless they were.
That only ever occured when there was an actual brown-out, not 10 minutes into startup. It is possible that the thing is too weak. but . . Init/post, and then startup is where the largest ammount of power is needed, usually not 10 minutes in, unless you are firing up a 3D game right after startup.
Test with the UPS removed? Do you have any other high consuming things on the same curcuit to begin with? refridgerator compressor, space heater, toner type printer (fuser), air conditioner, microwave? things that would cause a minor power surging?
Did you test the computer in safe mode? or with a few startup items turned off via Msconfig, or by stopping a few items in task manager before your 10 minutes runs out? What are the temps on the video card?