DX10 might be released soon, but it may be a while before games start using it, specially since there seems to be certain opposition to Windows Vista.
That PSU has two +12V rails at 10A and 15A, and the card specs at Newegg state: "450-Watt power supply or greater, 30 Amps on 12 volt rail recommended (assumes fully loaded system)". That PSU has 25A combined on the +12V rails, so I'm unsure whether it will run the card.
Edit: it seems PanzerKammander got ahead of me, hehe. Now, you state the +12V rails have 31A combined. What are your references? I based my observations on
this item. Is that your PSU, 95_GSX?
Edit2: lol, you edited while I was editing
. I agree with your remark, though: it may run the card, but it's a risk.