Is this UPS suitable for my rig?

it shoudl be fine, it shoudl give you about 2 mins of backup time providing the monitor is not plugged into it.
but idealy you want a line interactive ups, since it regulates the output voltage for you.
 
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In the past VA was the important rating, as VA is the apparent power, but these days most good PSU's active power factor correction, with an efficiency of 99%, so VA and Watts is almost identical. (with active PFC, you can expect a 99watt load, to use 100VA more or less).

So that UPS is 400W, sufficient for most systems, but occasionally you might find that a sudden peak load from your computer could overload it... Its prettty unlikely though to be honest. Of course, if you were to add extra hard drives, go SLI... then that might be pushing it. Anyway you'll get considerably longer runtime by using a UPS that isnt fully loaded.

On the whole, I would say that APC are a 'better' known brand for UPS's. Popular in commercial datacentres, and computer facilities. The APC RS800 VA would take you up to 540watts capacity, and might be just what your looking for. (Available at OcUK)

BTW, most UPS use sealed lead acid batteries. These gradually decompose during use, and are generally considered dead after 5 years. Dead leadacid batteries can short circuit and overheat, so regardless of what brand of UPS you pick, its worth checking the runtime is still 'ok'. It will lose about 10-15% of its runtime each year.
 
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psu internal efficiency is not 99% hence for example a psu rated at 400w with 80% efficiency is pulling 20% more than 400w from the mains to make its power.

the best type of ups is a online ups. second best is a line interactive ups.
in this country blackouts are rare so huge amounts of VA rating is not really necessary unless you have a whole bunch of machines u need to keep powered up for a while after a power cut.
get a ups that filters the power source so your 240v does not enter you psu as a 220v or 260v.
more stable power is a more stable pc.
 
Whatever you do shop about for the best prices! I run a 800va Belkin with a 19" LCD, X2 4200 and 3 x HD's + a GTX oh and the router is plugged into it as well.

Thats lot loads up a 800va about 49% according to the software they ship with. I get about 20mins of power with it also but generaly I just turn it off as soon as the power goes out. We have a PAYG meter so it happens quite frequently.

It has powered the Router on it's own for hours as well.
 
Cyber-Mav said:
psu internal efficiency is not 99% hence for example a psu rated at 400w with 80% efficiency is pulling 20% more than 400w from the mains to make its power.
Click to expand...

Quite right, I missed that :P. However it will still be pulling within 1% VA compared to Watts on the 240v side of things.

So if a 400w rated PSU, is supplying 400w to the computer, it will draw at least 500watts from the mains, and be around 505VA apparent power.

An older non active PFC 400W powersupply would have been more like 500W, and 833VA at full load. With UPS neither VA nor Watts should be exceeded.

The VA rating is nothing to do with the UPS's runtime, (well obviously the lower the load the longer the runtime), the runtimes are normally listed independantly, with external battery extensions often available if longer runtimes are needed.

Its quite possible to have a 400W 800VA ups with 15minute runtime, an hour runtime, even all day runtime. All depends on how many battery's are installed. The Battery capacity is measures in mAH (or simply AH). But you need to know the voltage of the battery pack, and the efficiency of the UPS to calculate runtime... Easier to just see what the spec says.

Thx to Cyber-Mav for pointing out the internal efficiency... but I was more refering to the difference between Watts and VA.
 
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my machine, as per sig, draws about 360 wall-watts when its working prety hard in a game. peaks about 400w. this is must the pc, no screens.

ive got a bit of a heavier load than you however - so id expect your closer 275w +/-50w loaded for your pc alone.

using an old 625vs ups, - stock 7ah battery swapped for a 12ah battery, i get about 15 mins runtime on a good day, flowing wind, not gaming (also powers a 19" crt + 17" tft)

i can get it to overload with prime + ati tool very easily.

- also, this is a very old, very cheap ups, so it behaves erratically. sometimes it switches to load support flawlessly, provides decent power at about 230v. other times it catches the load badly the output fluctuates +/- 100V (150-250v) with brief spurts of 0v and 300v this usually crashes the pc in 4-5 seconds and makes the crt turn off.

so be carefull to get a decent unit if you really need te uptime.
 
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