replaced rj45 lan input with a new lan card but runs very slowly

My motherboard is an Asus M3A78-EM and I have been using the system with the built in lan rated at 10/100/1000 mbps. The socket seems to be going bad so I tried replacing it with another internal card. They only had two to choose from at Office Depot were rated at 10/100/ mbps. and the other which was called D-Link DGE 530T which had the same specs as the motherboard so I got it. I've tried more than one cable and it works but is much slower did I buy the wrong thing to be running straight from a Wild Blue modem or, are there some settings that can be changed to speed it up I just run the one computer. Thanks! :) Newegg.com - D-Link DGE-530T Gigabit Desktop Adapter 10/ 100/ 1000Mbps PCI 1 x RJ45

Ztruker said:

Did you disable the onboard network adapter in BIOS Setup?

Try updating the drive via Device Manager, Driver tab, Update Driver then click on Search automatically for updated driver software.

I tried disabled and enabled left it enabled removed the card after removing the drivers then reinstalled the drivers first, per directions then the card again. I turned the pc back on the device was found and drivers were installed with success. It ran great for hours then, it started loading pages very slowly again? Then I plugged back into the onboard lan jack and it ran great, so I switched back to the pci card and got the same slow results again. I don't understand unless, my neighbor who also has wildblue can some how pull a drain off that card but I just have the dish which runs to my wildblue modem then to my pc nothing wireless? Maybe I just got a bad card any suggestions from anyone are sure welcomed. Thanks! :) Also, my neighbor is on s different sattellite.