RT-AX86U Poor wireless downlink performance

[two_face]

Hi, I've have AX86U for couple of months now and main purpose to get it was to comfortably use wireless file transfers from my NAS, instead of hooking up to wired connection each time. But I have strange behavior and now I want to sort it out. I have Intel AX200 client and when I'm saving some files to my NAS, I get strong 110 MB/s (full Gigabit) and this is great.
Problem is when I try to copy the files from my NAS to my laptop. It starts ok (about 70 MB/s) but then it drops drastically to 15 MB/s and from there its sluggish until the end. Here is the graph for better explanation:


Speedtests give me consistent 500 Mbps (my ISP speed) without such sluggish dropouts.
Any ideas what could cause such behavior?

 

[bbunge]

Single large file or multiple small files?

 

[two_face]

Its single file about 1 GB in size

 

[BobD]

You may need to manually trim your laptop drive. You may also need to adjust the trim interval.
Please indicate your operating system so you may get advice on these things.
Of course, you may also Google for them.
Another thought is that you have a cheaper drive and have exhausted the fast buffer. Then things will be at the much slower drive access speed.
Although it appears such, this is probably not a wifi question.

 

[degrub]

sounds about right for SMB V1 protocol. Monitor the % CPU on the NAS and the router (probably not the issue, but confirm). The first 70 MB/s is just buffer fill/dump. After that the transfer is struggling to keep the buffer full i expect. That can occur anywhere in the communication chain.
You can run iperf to document your local LAN and wireless throughput capabilities to try to find the bottleneck.

 

[two_face]

Thanks for the hints, my SSD was in raid mode (Intel Rapid Storage Tech...) so I turned it to AHCI and downloaded SSD Toolbox from manufacturer. It did some optimizations and it helped a bit. Now transfer goes down to ~30MBps and stays there. Still not ideal, but its a improvement.

Also, I've tried downloading to my fast USB drive, and it goes 110MBps. I guess its something with SSD (health is at 93%) but not sure why it happens because 6 months ago I could achieve transfers ~80MBps with other router. At least we can say that mystery is solved.