The second GPU is used to test whether the first one is defective or not. Many folks have more than one PC. A great way to troubleshoot is to swap a known, good device from one computer to another to verify whether something works or not.
I don't have any working GPU. I will buy one from bestbuy when I build the system if it did not work again.
fyi, I am one of those unfortunate one who got nVidia Geforce 8400 GS GPU. my Laptop sometime start and sometime do not start. so, I thought let me build the desktop now. HP do not replace it anymore as my warranty expire 1 month after the warranty period (2 yr).
bad luck buddy
once i bought CPU and it didn't accept to install windows vista (xp was perfect and so fast i don't know how and it's faulty i run game and it was very fast when i bought the other none faulty one it was not like the faulty )
i was going crazy because i am sure when i build something i build it right
so i tried every thing but none worked i went to the store i bought it from and
LOL the guy didn't look like he know what he is doing he thought it was the motherboard
but finally he know that something going wrong with the CPU it was faulty one
so i returned it and got me new one from another store