To get 1000Mbps on 1 computer, you will need hardware that supports speed greater than 1gig so for example you will be needing :
1.
Ont with 2gig port
2.
Router with 2gig ports
3. Nic with 2.5gig
Now this is not possible because of lack of onts and routers with such specs in home consumer market
It's the same like when you get 100Mbps. To get speeds over 100Mbps , you need
gigabit hardware everywhere otherwise the speed will just top at 90-95Mbps. So to get speeds over 1 gigabit, you need hardware that supports speed greater than 1 gig.