buying a UPS for my new PC

ve

good

Your PC is likely not running 600 Watts - more likely 100-200. That UPS will run it long enough to do an orderly shutdown or do you want to keep running for a while?

G=B2

Your PC will not be using 600 watts all the time if ever and your ups can supply a little more for a short time. "Good enough" is entirely in your opinion. Your new PC may have a setting to automatically shut down logically on power failure. I "guess" you will have time for that.

Tom

If it actually is still working at all, likely yes, if all you want is short power blips and shutdown fairly soon on power outage - and if the new computer can talk to the old UPS - if the UPS only has a serial port and the new computer only has USB, that can be an issue if you are not sitting in front of the computer when the power goes out. Power supply wattage is one of those numbers that marketeers crank up on the too-valid assumption that fools and their money will trend towards a bigger number. Your computer may never draw that much power even when it melts down. I happily tool along at 25% rated PS wattage or less most of the time, peaking at about half when off the rails in an infinite loop and winding up the fans. Spending $20-30 on a Kill A Watt can be quite informative, even if it's not the finest meter on the planet.

The bigger problem with an old UPS is that UPS batteries go bad (UPSes seem to have the lousiest battery maintaining circuits on the planet, with the possible exception of emergency lights.) As a class, they chew up and spit out sealed lead acid batteries like clockwork, so you might want to see what your old one does and consider replacing the battery if you find that it does not actually do what it claims to do (or for as long as it should) when the input power is shut off. New batteries are usually cheaper than a new UPS if the UPS is still working and does what you need it to. Sleaze-bay with careful shopping is generally (but not always) the cheapest source. You may be able to get a physically-same size but slightly higher amp-hour battery, also.