Ethernet Download speed question

Hi there,

I am running Mojave 10.14.6, and I got a download speed strange behavior.

Here is my env:

- My internet ISP is 1G speed
- ASUS X99-A onboard Ethernet I218V
- IntelMausiEthernet v2.5

When I use Speedtest to test my ISP speed, and I get the Download speed with 5xx Mbps, and Upload speed with 8xx Mbps. However, if I boot up with Ubuntu OS using the same server/hardware, I get the Download speed with 9xxMbps...

Ethernet Download speed question