any pics? i want to see this. this happened to my old FX5500...it was like a TK orb or something, and the fan stopped. the weird thing is, you say that the middle melted and bulged...i had a whole fan blade melt. the card was still good, so that brings me to a point. or nevermind, you have the rma thing.
yes it is great to have onboard, especially when the onboard has enough power to handle the games you play most. (halo, nfsu, nfsu2, some nes games, and yahoo games)
What brand was ur fx5500? and yes alot of new computers that have onboard can play newer games like halo 2 and they actually look good because they actually have pixel shader now.