This is Windows Phone. No, for real this time.” That’s what I thought when I started hearing about Windows Phone 8 a few months ago. Just like Windows Phone 7, it represents yet another clean break for Microsoft’s mobile ambitions — but unlike 7, now it’s got the hardware to match.

The truth is a little more complicated: this clean break isn’t as nearly as obvious as Windows Phone 7’s split from Windows Mobile was back in 2010. A quick glance at Windows Phone 8’s home screen, its apps, and its overall aesthetic lead you to believe that it’s only a mild evolution of Windows Phone 7.5 — and in many ways, that’s true. Much of Redmond’s grunt work instead went into overhauling what’s under the hood: these latest-generation phones now use what Microsoft calls the “NT kernel,” the same kernel that underpins Windows 8 and several generations of Windows for the desktop that came before it.

As much of an engineering challenge as that conversion may have been, the switch to the NT kernel is something Microsoft insists it needed to do. Amazingly, the framework lying beneath Windows Phone 7.x traces its roots back to Windows CE, Microsoft’s first attempt to port Windows to lightweight devices in the 1990s. It was never designed to accommodate today’s turbocharged smartphones — a market segment where features like multi-core processors are now the norm, not the exception.

But under-the-hood changes are tough sells for consumers drawn in by visuals and feature lists. So many of the questions raised by Windows Phone 8 are the same questions raised by Windows Phone 7.5 and 7 before it: is this finally the mobile platform that Microsoft (and Nokia) need to find widespread success?