I did a quick search for the kind of current that goes with nvidia's PSU wattage recommendation and found this list that has the current requirement at 24 amps. (Your PSU has 30 amps on the 12v rail)http://forum-en.msi.com/faq/article/printer/power-requirements-for-graphics-cards
If this information is accurate, your PSU can probably handle the card just fine.
-Not sure how much I trust the list though.
With a good brand PSU such as this one, I would probably do it if it were my own equipment. I'm less apt to advise others to take risks with their equipment, when I have no direct experience with the suggested risk.
Maybe someone with experience pushing this PSU near/past it's "official" limits will chime in.