Vid card fan slowing and starting up again please help

[powerup]

I have had this card about 4 days and it has run great till today. I turned on my comp today and I heard a fan slowing and starting up agian. I pulled off the panel to fgure out wich fan it is and I noticed right away it is the vid card. However if I turn the case on its side it goes away. Now for the last 10 minutes the fan is running just fine. This is the second card from gigabyte in the past month. I am not happy if I have to send it back again. any suggestions? Could this be my powersupply not powerful enough? I have an AIG 420 watt supply. Not a well known brand I know. Thank you

 

[powerup]

bump

 

[DrCrap]

I also have an issue with a gigabyte 6600gt fan. It makes alot of noise when the pc-case is standing up, but when I flip the case to its side the noise goes away. I getting a feeling gigabyte has done a crappy job on the HSF of this card, and I'm wondering if there's a good alternative (hsf) for it. Suggestions?