I have 2 GeForce 6600Gt cards. One I bought last year, and the other I bought recently. I wanted to hook them both up as I have an SLi board. Both my cards have labels attached to them and one says GeForce 6600GT PCX and the other says GeForce 6600GT PCI-e. I am confused. I thought that Nvidia's PCX was a lower quality GPU for these cards only GeForce PCX 5750, GeForce PCX 5900, GeForce PCX 5300. Is the label saying PCX a mistake or did they use 2 different GPU's for the same model?