How to send a large amount of data faster ?

@Wilberforce, I started this conversation after seeing that on arduino my boards were doing ~100kb/sec, while on espruino it was only 1kb/sec, for server a file. In fact, I am using espruino since the v1.91, and all that time I thought it was a hardware limitation of esp8266. But it seems to me that the problem comes from the dSnd buffer sent slowly, every 200m, in small pieces of 256bytes.

As it works faster on arduino, the board is not defective. It works the same way on the 2 nodemcu-e12 v2 & v3 that I have. I restarted the router, and tried AP alone (at 20cm from my laptop), station alone and AP+ST, still the same damn result !

@MaBe, I found it at ps-poll even though it was in AP+ST mode. No change when I set it to "none" using with Wifi.setConfig({powersave:"none"}).

@ClearMemory041063, I tried without improvement also flashing the last expressif firmware with the expressif flashing tool like you did, just in case. I used "esp_init_data_default_v05.bin", because there was no "esp_init_data_default.bin". I could not get it working without also changing addresses of this file and of "blank.bin" to 0x3fc000 and 0x37e000. I got a nice :

AT+GMR
AT version:1.4.0.0(May  5 2017 16:10:59)
SDK version:2.1.0(116b762)
compile time:May  5 2017 16:37:48
OK

Then I reflashed espruino, this time with expressif flashing tool. I used the files from this url. I used the addresses from your link and I tried with "blank .bin" at 0x3FE000 like I used to do, both works same way. Still as slow as before.

I tried other browsers too, older espruino versions (v1.91, v1.94). The strangest that no one else ever have or noticed this problem before.

 _____                 _
|   __|___ ___ ___ _ _|_|___ ___
|   __|_ -| . |  _| | | |   | . |
|_____|___|  _|_| |___|_|_|_|___|
          |_| http://espruino.com
 1v95.155 Copyright 2017 G.Williams
Espruino is Open Source. Our work is supported
only by sales of official boards and donations:
http://espruino.com/Donate
Flash map 4MB:1024/1024, manuf 0xef chip 0x4016
>Start connection process
Try Connecting to WiFi  Gardening, cheaper than therapy
=undefined
Test for error
Test for error
Test for error
null
connected? err= null info= {
  "ip": "192.168.2.6",
  "netmask": "255.255.255.0",
  "gw": "192.168.2.1",
  "mac": "2c:3a:e8:0e:9f:1c"
 }
Wi-Fi Connected
n= 4 t: 0.018 sec
n= 3 t: 1.711 sec
[WS] "Hello to Espruino!"
n= 2 t: 3.186 sec
[WS] "Hello to Espruino!"
n= 1 t: 4.691 sec
[WS] "Hello to Espruino!"
n= 0 t: 6.165 sec
[WS] "Hello to Espruino!"