LAN Ethernet Controller Slow - Limited Connection?

Network Adapter (as displayed in device manager) Realtek PCIe GBE Family Controller (says this device is working properly)

Motherboard chipset
Intel p67
Processor
i5 2500k
Windows 7 x64

I'm running my lan on the integrated network adapter "Realtek PCIe GBE Family Controller" on my motherboard. When I plug in the lan line directly from my router the speed on speedtest.net is around 2 Mbps, i have tested on 2 other computers and they all get around 10 Mbps with the same line. I build this new machine to play games, and sank $800+ on it. I am trying very hard to figure out why my LAN speed is so slow.

I am worried it is a mother board defect, but it is unlikely as I can still browse the internet and stream video. I just get slower download speeds and more lag in games which defeats the purpose of building a gaming computer . I have disabled my avast and my windows firewall to test the speed.

I have also tried buying a wireless card (Netgear N300 Wireless PCI Adapter) and it peaks at around the same 2Mbps. My other computers get 6+ Mbps wireless on speedtest.net at the same location from the router.

Because both LAN and wireless seems to be caping out at 2Mbps could this be an indicator of some sort of internal limiter on internet speed? Or even worse, hardware defect? I'm going to get a USB wireless adapter tomorrow and test the speed.