jsdom appears to favor its default parser vs another when they are used in the same script?

bothparsers.js

var  jsdom = require('jsdom@0.2.0')
	,fs = require('fs')
	,testHtml = fs.readFileSync(__dirname + '/british_throne.html', 'utf8')
	,html5 = require('html5')
	,window
	,document
	,start = +new Date()
	,end;


start = +new Date();
window = jsdom.jsdom(testHtml, null, {
	features: {
		FetchExternalResources : false,
		ProcessExternalResources: false,
		QuerySelector: true,
		MutationEvents: false
	}
	//,parser: html5
}).createWindow();
document = window.document;

end = +new Date();
console.log( (end - start) + ' ms to load' );


start = +new Date();
window = jsdom.jsdom(testHtml, null, {
	features: {
		FetchExternalResources : false,
		ProcessExternalResources: false,
		QuerySelector: true,
		MutationEvents: false
	}
	,parser: html5
}).createWindow();
document = window.document;

end = +new Date();
console.log( (end - start) + ' ms to load' );

// each take about 10 seconds on my core i5 !?

defaultparser.js

var  jsdom = require('jsdom@0.2.0')
	,fs = require('fs')
	,testHtml = fs.readFileSync(__dirname + '/british_throne.html', 'utf8')
	,html5 = require('html5')
	,window
	,document
	,start = +new Date()
	,end;

start = +new Date();
window = jsdom.jsdom(testHtml, null, {
	features: {
		FetchExternalResources : false,
		ProcessExternalResources: false,
		QuerySelector: true,
		MutationEvents: false
	}
	//,parser: html5
}).createWindow();
document = window.document;

end = +new Date();
console.log( (end - start) + ' ms to load' );

// takes about 10 seconds

getHtml.sh

#!/bin/bash

# I'd put the html into the gist, but it breaks github's servers because it's so large!

curl http://en.wikipedia.org/wiki/Line_of_succession_to_the_British_Throne > british_throne.html

html5parser.js

var  jsdom = require('jsdom@0.2.0')
	,fs = require('fs')
	,testHtml = fs.readFileSync(__dirname + '/british_throne.html', 'utf8')
	,html5 = require('html5')
	,window
	,document
	,start = +new Date()
	,end;

start = +new Date();
window = jsdom.jsdom(testHtml, null, {
	features: {
		FetchExternalResources : false,
		ProcessExternalResources: false,
		QuerySelector: true,
		MutationEvents: false
	}
	,parser: html5
}).createWindow();
document = window.document;

end = +new Date();
console.log( (end - start) + ' ms to load' );

// takes approximately 70 seconds