I want to buy the radeon 4890. But I have a weak power supply. There is a list on readeons website of recommended power supplies that they have certified for use with the 4890. I just want to know how important it actually is that you get one of these certified power supplies. The only store in my city that carries the 4890 does not sell any of the certified power supplies. I want to get the store to do all of the installing. I am afraid I could muck something up.