An Intel NUC11TNHi7 PC with I225-LM 2.5Gb Ethernet connected to an Orbi RBSE960 satellite 2.5Gb LAN port exhibits low & erratic file copy throughput.
Instead of an expected steady ~130MBytes/sec throughput, the figure drops as low as 5MBytes/sec and fluctuates significantly during the file copy done via a mapped network drive of a file server. See attached screen shot.
Tested system configuration:
* PC: Intel NUC11TNHi7 PC (BIOS TNTGL257 0064 - latest)
* File Server NIC: Sabrent NT-55SG USB-to-5GbE adapter (OS=Windows Server 2022, NIC driver: Aquantia 1.8.0.0)
The PC is connected to Orbi RBSE960 satellite 2.5Gb LAN port via 15' CAT5e cable
The File Server is connected to Orbi RBRE960 router 2.5Gb LAN port via a TP-Link TL-SX105 5-port 10G/Multi-Gig Ethernet switch & 25' Cat6A cable
Attached screen shot displays the low/erratic file copy throughput.
For troubleshooting, I replaced the PC's I225-LM 2.5Gb Ethernet with a Sabrent NT-55SG USB-to-5GbE adapter (same model as used with my File Server) attached to a USB 3.0 port, and the file copy throughput is steady at ~130Mbytes/sec, which I believe is near the sustained throughput of the backhaul between Orbi router & satellite in my home setup.
Another change tested was to manually force the Intel I225-LM Ethernet to negotiate at 1Gbps full duplex, instead of Auto. This prevents the I225-LM from negotiating the 2.5Gb speed but restores the file copy throughput to a steady ~110Mbytes/sec, which is essentially line speed for 1Gbps.
A separate test of the Intel I225-LM Ethernet connected directly to the Orbi RBRE960 router (via a TL-SX105 10GbE switch) yielded ~280MBytes/sec file copy throughput.
A second NUC11TNHi7 PC running Windows 10 PC was also tested in conjunction with the same Orbi RBSE960 satellite and yielded identical results vs. the first NUC11TNHi7 PC.
I would therefore characterize the erratic Ethernet throughput as an interaction issue between Intel I225-LM Ethernet and Orbi RBSE960 satellite at the 2.5Gbps link speed. The I225-LM Ethernet and the Orbi RBSE960 satellite each by itself can sustain >1Gbps throughput at the 2.5Gb port, but when connected together, the throughput becomes erratic, and can drop as low as 5MBytes/sec. It is difficult for me to tell which of the two devices (I225-LM or RBSE960) is responsible for the erratic throughput, as issue reproduction requires these two devices to be interlinked at 2.5Gbps Ethernet.
