Microsoft's new Spartan engine masks itself as Chrome

Microsoft has released the latest build of Windows 10 to Insiders packed full of surprises, some more obvious than others. Luckily, we have a community of enthusiasts that search its insides, even in the darkest corners, and David Storey from the IE team that helped us uncover a rather interesting bit in build 9926.

He shared on Twitter how to enable the new Trident engine that Spartan and Internet Explorer will share on Windows 10, and the process is the same that worked in earlier builds. You type about:flags in the address bar and you turn set the flag to enabled for "Enable Experimental Web Platform Features".

…if you install the Win 10 tech preview, enable about:flags to get the new browser engine. This is engine going in Project Spartan
— David Storey (@dstorey) January 23, 2015

The interesting part is that by doing this, Internet Explorer no longer reports the normal User Agent String, which is "Mozilla/5.0 (Windows NT 6.3; Trident/7.0; rv:11.0) like Gecko". As you can probably see in the image above, Internet Explorer now masks itself as Google Chrome, which David actually confirmed that is being done on purpose, as a workaround for a very unusual behavior.

@obiwankimberly @ie on purpose. I invite you to do site compat outreach if you disagree :)
— David Storey (@dstorey) January 25, 2015

Many websites that you visit today will not display well in IE because they are not coded properly and usually display a page like they would in an old browser, even though Internet Explorer 11 supports many of the new web standards. Some pages will display incorrectly in IE while working perfectly fine on other browsers such as Chrome or Firefox.

There's also a problem with jerky scrolling that doesn't go away for some websites even after you turn off smooth scrolling, and there are cases in which important elements will not display because a webpage identifies your browser as IE.

When Microsoft mentioned that Spartan will be suited for the modern web, they weren't kidding. We've done some tests in Google's Octane benchmark, and IE with the new Trident engine scored 19312 points, while Chrome 40 managed only 17402. This is consistent with other reports in showing that the new engine is already well optimized for speed.

When we tested for HTML5 features, we found improvements there as well. IE with the new Trident engine now gets 351 points on html5test.com, up from 336 points for Internet Explorer 11. Many features are probably not even recognized because everything is in an early stage, but we'll test again when a new build comes out.