Wan->lan 25mbit speed drop with wifi enabled on QCA9531/QCA9533

Hello, I noticed strange issue after updating from chaos calmer to the new lede/openwrt. When wifi is disabled, I get about 90mbit down speed (from 100 possible), when I enable wifi, wan to lan speed drops to 65mit :open_mouth: I downgraded back to chaos calmer and it is fast again no matter if wifi is up or down. No wifi station was connectected during the tests.

I can see the same behavior on routers tp-link wr841n v10 (QCA9533-BL3A) and wr842nd (QCA9531-BL3A). I believe the same problem exists on different 100mbit routers with atheros. On wr1043nd (QCA9558) which has gigabit ports I don't see this issue. I don't think it's CPU problem, wr841n and wr842n has fast 650MHz CPUs and load is less than 10% during speedtest tests on both CC and lede. NIC % load corresponds actual measured speed.

I believe designated driver was ok too, so it must be some new "feature" in lede. Someone noticed this too? May I report it as a bug?

I think I meet the same problem.
have you find the root reason ?

Unfortunately not, I'm still waiting someone comes up with something.

I meet the problem same like you,
we compile the lded4.9.77 for lte router at QCA9531 16M 64M motherboard , the new lede firmware only can get 30Mbps download, but the old openwrt CC can get 75Mbps download speed.
I guess the new lede 4.9 must have some problem in Lan speed.

I just wondering the fast path active in new lede ? Qualcomm Fast Path For LEDE