I have YOUKU YK1 (MediaTek MT7620A) with openwrt 18.06.2. When I transfer files from clients to my router via wifi I only get about 1-2MBps or sometimes even worse. Here's my /etc/config/wireless content:
[manjaro@linux tmp]$ scp -C /run/media/manjaro/Data/Movie/The.Dark.Knight.2008.BluRay.720p.Ganool.se.mkv firstname.lastname@example.org:/mnt/usb2
Warning: Permanently added '192.168.1.1' (ECDSA) to the list of known hosts.
The.Dark.Knight.2008.BluRay.720p.Ganool.se.mkv 2% 25MB 1.4MB/s 13:34 ETA
Is there a way to make the transfer speed faster ?
That pretty much aligns to your wifi performance. SCP using dropbear is slow (well documented) and your rather slow SoC doesn't make it any better. From what I recall anything else by Ralink/Mediatek than isn't supported by the mt76 driver does have poor performance which seems to apply to your device as there are no additional drivers added to the image. https://github.com/openwrt/openwrt/blob/master/target/linux/ramips/mt7620/target.mk#L10
@vgaetera Yes it is true for most of the low-end devices but hardware performance can be improved through improving software and this is the case for xrx200 based devices. If you look into this thread you may know that with some patches we were able to increase the overall performance of the SoC through IRQ balancing. I am not really sure if all of the patches did the trick but I am able to get more than 100mbps out of 150mbps from Wifi while downloading and around 70mbps average while uploading without any use of Flow Offloading.
In this case @diizzy 's answer might be more related. I have not tried SCP myself but I did try iperf3 and have amazing speeds, more than 100mbps ethernet. Test logs are also available in the thread but it's also possible that the driver support can be improved in future so it may increase performance.
Maybe another 1mb/s at most in my opinion. AFAIK iperf3 uses whole CPU so if it cannot provide any improvement in transfer speeds then dont count on Samba as well. You can try to force 40mhz on your Wifi and it may provide somewhat better results.