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#11
So I should be good spending my 300$ on it? With no worries of psu failure lol?
As posted elsewhere, have a look at another wattage estimator:
eXtreme Outer Vision - eXtreme tools for computer enthusiasts
It doesn't include the 5850, but the 5870 is on the list. (The 5870 needs more power, although it uses the same connectors.)
Looks like a good 400W PSU could be adequate. However, as others have posted, you may not get long service from a PSU that is run flat out for extended periods.
Your PSU is rated at 16A on each of its three +12V rails, which suggests that it's a reasonably good 650W unit. You need 75W (6.25A) on each PCI-E connector, so even if both of your PCI-E connectors were on the same rail, you'd have margin (if no other devices were on that rail.)
You'll get lots of help online in spending your money. I can't swear that your PSU will be adequate, but I'd risk it if it was mine.
I use a PC Power & Cooling Silencer 750. It worked fine with an overclocked I7 920, plus a pair of 4870s in Crossfire. It's rated at 60A on its single +12V rail, though. I'd recommend it as a robust PSU that doesn't cost a fortune (if you fear that yours will meet an early demise).