MKR4000 very slow compare to MKR1010 ? - WIFI communications very slow !

I ran the attached demo (basic web server) on both a MKR1010 and MKR4000 board.
On the MKR1010, the demo is functional as to say, the web page is served and rendered fast enough but on the MKR4000, it takes ages to render the page !
It seems the MKR4000 board is running much slower than the MKR1010 !? Why ?
Is the M0 running at a lower clock speed ?
The SPI communication goes thru the FPGA according the schematics, not directly from the MCU to the uBlox Wifi module as on the MKR1010.
Any ideas welcome !
Thanks, J. (46 KB)

Just bought an MKR4000. Going through the very same issue, MKR4000 WiFi being much slower than MKR1000 one.

CPU speed is not the issue (tested). Wifi signal level not too (tested).

Did you progress in your investigations ?

Other topic, that I created before I found this one: Major performance issue with MKR4000 vidor compared to MKR1000 doing fine - Programming Questions - Arduino Forum