PSU for 8800GTX

I'm upgrading my system in about a months time, but have got annoyed with some of the games I own stretching my PC a bit so went and bought one of the 8800GTX's that will be in my new system for use in my old system to tide me over. At the moment my system is:

Athlon 64 3500+ (Winchester)
1gb RAM PC3200
ATI x850 XT PE
DFI NF4 Ultra
1 x 120gb PATA HD
2 x 250gb SATA HDs
Augidy 2
DVD-RW
DVD-ROM
OCZ Powerstream 520w

Using a system power calculator the system with the 8800GTX goes up to about 397w at peak consumption. Given 80% efficiency I can expect around 420w from my PSU. Question is, am I going to be pushing it using that 520w PSU, or should I also go a head and get the 850w Enermax Galaxy I'm planning on getting anyway now as well? Answers on a postcard to the usual address!

You'll be fine.

The question is less about totally wattage these days, and more about A on the 12v lines, but I think your current PSU is pretty good.

Should be ok, though i had the same PSU a week ago, and now it's dead.:) after 2 years.