I believe speed above 300Mbps is very depends on device specification.

I am using 500Mbps not the 800Mbps but not all my device manage to reach 500Mbps also.
Following test result had run multiple times in different day.

Basic Item
- Maxis Fibre 500Mbps
- Using Maxis router.
- All LAN cable is cat7 which is 1000Mbps (Both computer detect as 1000Mbps connected)
- Wireless is connected at 5Ghz Wi-Fi.

Result
- New PC (1 year ago) - around 540Mbps
- Old Laptop (6 years ago) - around 330Mbps
- Apple TV 4K (2021 edition) - around 480Mbps
- Samsung Galaxy Fold3 (wireless) - around 390Mbps
- Chromecast with Google TV (wireless) - around 310Mbps
- LG C9 TV - around 100Mbps

This post has been edited by Andrewtst: Mar 23 2022, 06:01 PM