At the moment the code has no keyboard so to be able to get past BIOS boot the irq1 line is flodded with keyboard presses. This slows the emulation down.
The ESP8266 runs at 160MHz and makes the emulated 8086 run at about 300K instructions per sec, nearly the same as the original 4.77MHz 8086.
Once keyboard code is added it is actually very useable.