boom!!! Here is a hack solution to make atom start faster. For Atom <= v0.170.0

atom.js

     Atom.prototype.startEditorWindow = function() {
      var CommandInstaller, dimensions, maximize, resourcePath, safeMode, _ref;
      _ref = this.getLoadSettings(), resourcePath = _ref.resourcePath, safeMode = _ref.safeMode;
      CommandInstaller = require('./command-installer');
      CommandInstaller.installAtomCommand(resourcePath, false, function(error) {
        if (error != null) {
          return console.warn(error.message);
        }
      });
      CommandInstaller.installApmCommand(resourcePath, false, function(error) {
        if (error != null) {
          return console.warn(error.message);
        }
      });
      dimensions = this.restoreWindowDimensions();
      // this.loadConfig();    
      this.themes.loadBaseStylesheets();
      this.keymaps.loadBundledKeymaps();

      setImmediate((function(_this) {
        return function() {
          _this.deserializeEditorWindow();
          _this.themes.activatePackages();
          _this.packages.activatePackage("tabs");
          _this.packages.activatePackage("status-bar");
          _this.packages.activatePackage("tree-view");
          
          _this.loadConfig();
          setTimeout(function(){
            _this.packages.loadPackages();
            _this.watchProjectPath();
            _this.packages.activate();
            _this.keymaps.loadUserKeymap();
            if (!safeMode) {
              _this.requireUserInitScript();
            }
            _this.menu.update();
            _this.subscribe(_this.config.onDidChange('core.autoHideMenuBar', (function(_this) {
              return function(_arg) {
                var newValue;
                newValue = _arg.newValue;
                return _this.setAutoHideMenuBar(newValue);
              };
            })(_this)));
            if (_this.config.get('core.autoHideMenuBar')) {
              _this.setAutoHideMenuBar(true);
            }
          }, 200); //NOTE: here can change
        };
      })(this));

      // this.packages.loadPackages();
      // this.deserializeEditorWindow();
      // this.watchProjectPath();
      // this.packages.activate();
      // this.keymaps.loadUserKeymap();
      // if (!safeMode) {
      //   this.requireUserInitScript();
      // }
      // this.menu.update();
      // this.subscribe(this.config.onDidChange('core.autoHideMenuBar', (function(_this) {
      //   return function(_arg) {
      //     var newValue;
      //     newValue = _arg.newValue;
      //     return _this.setAutoHideMenuBar(newValue);
      //   };
      // })(this)));
      // if (this.config.get('core.autoHideMenuBar')) {
      //   this.setAutoHideMenuBar(true);
      // }
      maximize = (dimensions != null ? dimensions.maximized : void 0) && process.platform !== 'darwin';
      return this.displayWindow({
        maximize: maximize
      });
    };

The Path on Mac isn't exist, can you update it please?