With Samsung EVO850 SSD I got read speed about 25MB/s, write speed about 20MB/s. ntfs-3g process takes about 20% cpu load. Maybe with other FS speed will be better because NTFS makes more load than others AFAIK.
I have used this router on a 300/300 link for a few months now and based on what I am observing, this is its ceiling for real life use cases: it can only deliver ~300Mbps combined throughput WIFI to WAN (I ran several tests downloading lots of data from one cloud and immediately uploading the files to another to confirm that). Both router cores are at ~95% while only uploading or only downloading or combined. Needless to say, that the router from my ISP can handle bi-directional traffic at full speed.
No QoS or SQM and software flow offload is enabled. Does anyone observe faster speeds?
I don't know if you have tried balancing the irq's, this make a noticable improvement on the linksys series. You could also try observing the throughput by forwarding packets from the lan port to the wan port bidirectionally using iperf and two computers if possible via ethernet.
EDIT: I looked over the part where you mentioned wan throughpout to be expected.
Speed tests have changed over the last couple weeks due to COVID, speedtest has been tracking the changes, most places are still seeing degradation in service. Speed tests have been varying every day. I wouldn’t be too frustrated by speed tests for the next couple weeks until things get a little more normal.
Some of the older macOS clients don’t support AC. I recently retired a Mac laptop with a wireless N adapter (don’t know the age of yours. For me the wireless speed...slowness...was starting to become very noticeable):
Apple has a good write up on macOS clients. I’d evaluate your environment settings to get the best balance for your clients.
Especially: “macOS always defaults to the 5 GHz band over the 2.4 GHz band. This happens as long as the RSSI for a 5 GHz network is -68 dBm or better.”
Doesn’t take many obstacles for 5ghz to drop to -68 dBm. I’ve found it better to split the 5 and 2.4ghz SSIDs (and have my higher performance clients forget the 2.4ghz SSID) so that I retain the higher performance of 5ghz. There is much more bandwidth and less interference from household items on 5ghz.
do a survey of your local area and pick a channel rather than going with Auto. Pick a 80Mhz wide non DFS channel - 36 or 161.
Thx, but I already did all these basics steps without any improvements. My laptop does support AC and the auto channel works great and does pick the best channel, even though I tried setting different channels manually.