Difference between firmwares esp8266_4mb and esp8266 ?

1v95.20 Copyright 2017 G.Williams

This is how the release 1v95 looks like:

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|   __|_ -| . |  _| | | |   | . |
|_____|___|  _|_| |___|_|_|_|___|
          |_| http://espruino.com
 1v95 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 0xe0 chip 0x4016
>process.env
={
  "VERSION": "1v95",
  "BUILD_DATE": "Dec 15 2017",
  "BUILD_TIME": "12:59:13",
  "GIT_COMMIT": "da2dc33d46082cc1d3b28092995123a8a6a2417­5",
  "BOARD": "ESP8266_4MB",
  "CHIP": "ESP8266",
  "CHIP_FAMILY": "ESP8266",
  "FLASH": 0, "RAM": 81920,
  "SERIAL": "5ccf7fc1-120b",
  "CONSOLE": "Serial1",
  "EXPORTS": { "jsvLock": 1075854228, "jsvLockAgainSafe": 1075854316, "jsvUnLock": 1075854940, "jsvSkipName": 1075864796,
    "jsvMathsOp": 1075871204, "jsvMathsOpSkipNames": 1075872992, "jsvNewFromFloat": 1075862156, "jsvNewFromInteger": 1075862040, "jsvNewFromString": 1075861816,
    "jsvNewFromBool": 1075862124, "jsvGetFloat": 1075868928, "jsvGetInteger": 1075864092, "jsvGetBool": 1075869304, "jspeiFindInScopes": 1075887224,
    "jspReplaceWith": 1075886908, "jspeFunctionCall": 1075898260, "jspGetNamedVariable": 1075889136, "jspGetNamedField": 1075889580, "jspGetVarNamedField": 1075889712,
    "jsvNewWithFlags": 1075861420 }
 }
>process.memory()
={ "free": 1562, "usage": 38, "total": 1600, "history": 10,
  "gc": 35, "gctime": 1.712 }
>var g = Graphics.createArrayBuffer(8,8,8);
=Graphics {
  "buffer": new ArrayBuffer(64)
 }