wifi and ethernet slow on iMac with macOS catalina ( upgraded from mojave)
Speedtest telenet from imac https://telenet-prd.speedtestcustom.com/result/0a19d010-2a1f-11ed-8a5b-390ab9678654 with ethernet connected to modem/router of telenet.be provider very slow in download ( 47.8 Mbps download, 38.2 Mbps upload ) when compared with others devices iphone 7, android phones, lenovo workstation with similar hardware capabilities ...
Speedtest telenet from lenovo workstation with same physical connection is five times better ( 382.2
Mbps download but same speed upload than imac : 38.2 Mbps ) : https://telenet-prd.speedtestcustom.com/result/91180790-2a1e-11ed-911f-334e3d72af54
The capability provided by the internet provider with this modem/router is : 400 Mbps download, 40 Mbps upload ) and the ethernet interface of my iMac late 2015 is 1 Gbps.
Any explanations/solutions ? ( N.B. exactly same performance issue with Wi-Fi 5Ghz )