There are quite a few things you can do:
Make sure power save is off on your client.
Make sure no other devices/clients are on the same channel.
Make sure that there is an obstacle between your laptop and the access point so that you can leverage multipath
If you are using iPerf to measure throughput, make sure you use a Window Size of at least 512K
Make sure that you have "Drop Broadcast and Multicast" enabled on your Virtual AP.
Sometimes the limitation is how fast each device has access to the disk subsystem.
How the WLAN driver aggregates and de-aggregates the packets can drop the throughput.
A file copy is not optimized for wireless throughput, so you can only get so much performance while copying.
Long story short, nobody ever achieves speeds of 450Mbits/sec or even half of that. The ones that achieve that do it in the lab, with no interference and with client Window sizes tuned up to 512K on both sides, and most clients are not tuned that way, so that is probably unattainable in the real world.