Faster SD card write on marlin over wifi

Hello everyone,
I was trying to connect an esp8266-01 board to an AIO II, v3.2. I got the wifi connection up and running, with esp3d i have the whole setup working now. I was just wondering how I could get the SD upload over wifi to be faster.
1.Does anyone know what the speed of the transfer is currently with a similar setup?
2.Does anyone know what the actual bottleneck is in this chain?

upload to sd is over serial, so is limited to the baud rate you set in esp3d

wifi -> serial -> controller -> sdcard.

some are trying to implement meatpack serial compression to double the transfer speed... its not there yet.

There are two way around the slowness

1) use octoprint. It saves to its own sdcard and just prints over serial. upload is limited by wifi speed
2) use a controller with USBCDC serial (ie usb goes directly to the controllers chip) these upload at 12mbs and ignore the set baudrate. most lpc1768/9 based boards do this,

Edited 1 time(s). Last edit at 03/24/2021 04:13AM by Dust.

Thanks a lot @Dust. The second option would still require a lot of firmware changes right ?

And I actually tried to change the baud rate to a higher value(picked the highest common baud rate in the firmware for both of the devices), a lot of things started malfunctioning and for a slightly lower baud rate, only the file manager stopped working on the webUI.