XPS 8300 power supply and ups requirements

Thanks for your input on this.  Much appreciated.

First, Dell tends to underrate their power supplies.  That is probably more like a 500 watt (continuous) unit. 

As far as the UPS, it depends on the actual UPS and it's switching time and the particular Active PFC Power Supply.  Some of the non "sine wave" output (on battery) units will still work with Active PFC power supplies and from posts on here and other forums those have less than a 4MS switching time.  Can't guarantee that all with less than 4MS will work as it depends on the actual PFC power supply.   The Cyberpower units that have the true sine wave have been reported as working OK. 

I have a home built PC with an 850 watt Active PFC power supply and an older Dell branded APS UPS system and it is working OK - no dropouts when it switches to battery backup. 

Bottom line, can't say for sure what you will actually need. I know you wanted a definitive answer but with the variables can 't say for sure.

I just ordered this PC myself.   I was wondering the same. Are there any owners out there who can share their experiences with UPS and Dell XPS 8300? What type of power supplies have people been finding in these machines, active PFCs?  Brands/models of UPS battery backups that are working for you folks?

Sorry to resurrect this old thread... but I'm also wondering if the 8300 has an active power supply.  I actually have the sine UPS, but just wondering about my power supply.  How do I find out if the 8300 has an active power supply or not?  Thanks!