I'm investigating slow speeds to my QNAP NAS. I suspect because the NAS is old (10+ years) and the load (via putty > top) is always 6+ I'm planning to replace it, but I want to make sure it's not my network that's causing the issues.
All clients are connected to a Unifi AP Lite at 5GHz. All very close to the access point.
But then I started to investigate further. When I run an internet Speedtest on any device, I get my maximum internet speed of 100Mbps. When I run an iperf3 server though and test between WiFi devices, or from a WiFi device to a Raspberry Pi4, I only get about 30-40 Mbit/sec? I'm running iperf3 from either Windows or Android client devices, and have tested as server on a Raspberry Pi4 and a Windows machine. All similar speeds, 40Mbit/sec.
Network topology is a 8-port Gbit switch with Raspberry Pi4 & QNAP TS-412 connected, and the Unifi AP Lite.
Why do I get such low speeds when running iperf3? Why seems my LAN speed slower than my internet speed?