That link says the card uses 230W. If the rest of the system uses ~100W, that means you'd be running at 350W or so. I think it'd work fine. I wouldn't advise overclocking anything though. They recommend more than required to make sure people don't use bare minimum power supplies. If they said all you need is 500W then some people would use the cheapest 500W PSU and of course it won't work.