What are your network interface card specs on each laptop?
are you using the same router for both?
check your line speed should be set to fixed 1000 duplex if your ISP provides to you at 1000 Mbps
lastly does your router support GigaE
finally what type of ethernet cable are you using? I use Cat 7 or at the very least Cat 6a Giga E cable all support 1 Gbps and cat 7 will support up to 40 Gbps providing you have the nice network interface cards onboard. the Intel makes a nice card, expensive albeit but worth it.
Hope this helps