Over the past couple of days, I've been working on a networking issue regarding the 2.5GbE port. Long story short: I've been upgrading my switch and a few devices to greater than 1GbE speeds. Synology DS1618+ and QNAP switch are 10GbE, and my hack is currently 2.5GbE. I've narrowed the issue down to
read speeds only on the 2.5GbE port (1GbE port works at max bandwidth on both read/write). For some reason the read speeds top out at around 80MB/s on the 2.5GbE port. Read/write speeds are max throughput from Windows; no issue. I've already exhausted most of the common troubleshooting options (SMB settings, signing, encryption, MTU, etc.) so I'm 99% sure it's something (driver?) related to just the 2.5GbE port under macOS (Catalina and Big Sur).
Is there anything I can do in the OC config to troubleshoot the issue?
I'll eventually upgrade to this
Syba 10GbE card, but I thought it's worth finding a solution in case anyone else has a similar issue.
Side note: in Big Sur, System Prefs>Network>Advanced>Hardware>Duplex is set to full-duplex, flow-control by default (when switching from Configure: Automatic to Manually), whereas in Catalina it's just set to full-duplex. I've read somewhere that ethernet flow-control is not preferred, but I'm no IT guy. I haven't noticed a difference either way in any of my troubleshooting.