Nope, that UPS isn't big enough for your pc. It would easily shut down if you were in a game. I can draw over 600W with the stuff that is in my sig. (Monitor included)
There is a 1200VA model from them that would probably keep your pc up for about 5 minutes, which is just long enough to shut the pc down before you run out of juice.
I'd probably suggest the 1500VA model for a rig like yours as it can definitely suck down the juice. http://www.newegg.com/Product/Produc...82E16842102054
I use one of these right now:
It's a little bit more than the Cyberpower unit but it's from a well known name and has worked well for me so far. Just recently I had to replace the battery in one of my units (They last between 3 - 5 years) and I can go right to APCs site and order a new battery. It includes free shipping and disposal for the used one. As of right now Cyberpower doesn't sell any replacement batteries for their units so you'll have to find someone who does. We use all APC units at work so it was the first choice for me.
I can't say as I've heard anything good or bad about Cyberpower so you might want to do a little browsing. Just keep in mind that bigger is usually better and the extra $30 or so for a 1500va model should allow your unit to handle more equipment if needed and possibly add another minute or two of runtime. You have a couple grand in computer equipment so it makes sense to guard it with a solid UPS. If for some reason your stuff gets fried you can send them the broken parts and they will replace anything that was damaged.
EDIT: I vaguely remember this test, but I know I was running a benchmark of WiC on my pc. I'm pretty sure this is only the tower and no monitor (2407 = 70W). If my BR900 would have needed to kick over to battery it would have just shut down as the overload light was on.