Windows 8 may be fast , and it might turn that old PC of yours into " Greased Lightning ", but according to a usability expert that new user interface gets in the way of users actually being able to use the new operating system.

Raluca Budiu, a user experience specialist with Nielsen Norman Group, claims that the new user interface -- previous called Metro but now renamed Modern UI by Microsoft -- is "confusing" and imposes "a cognitive burden" on users.

In other words, people have to think too much.

Speaking to Laptop Magazine, Budiu claims that Windows 8 is "confusing" because the user has to remember which apps are running on the desktop rather than just being able to switch to them directly with a single click, as with previous versions of Windows. Windows 8 doesn't give users a way to see which desktop apps are running when in the Metro Start Screen.

Budiu also highlights a number of problems relating to using Windows 8 with a mouse. Microsoft's decision to hide menus not only slows the user down, but also makes the menus themselves less likely to be used.

"The fact that the menus are hidden is primarily what slows users down," says Budiu. "Remember that what's out of sight is out of mind. In our studies with mobile devices we found that whenever a menu was not in plain view, even users who knew about the existence of that menu didn't use it as much or took a longer time to think to use it than if the menu options were all visible. So it's not only the hovering that slows users down -- it's the lack of visibility that makes these menus less available".

There's also criticism in Microsoft's decision to take what it thinks works on mobile platforms, to then apply this to desktop systems with larger screens.

"The idea of hiding the controls to give priority to content may make sense on mobile, where screen space is so limited, but it doesn’t make that much sense on a large screen, especially if users have to work harder to access hidden features".

Budiu lambasts Microsoft's move to shoe-horn together two user interfaces into a single operating system. This, she claims, will cause "a cognitive burden" for users as they have to remember how each user interface works and "is likely to confuse at least some of the users".

Enterprise users who are thinking of deploying Windows 8 should take note of the fact that Budiu goes on to say that the Windows 8 learning curve "is going to be steep".

This claim alone should act as a warning to anyone thinking of putting Windows 8 in the hands of thousands of users in an environment where you expect people to get work done. Training costs could eclipse the costs of deploying Windows 8, and offset any savings that the new operating system might offer.

Back in June, I called Windows 8 a "design disaster." As much as I like the speed and performance gains that the new operating system brings, and despite being rock-solid, snappy and responsive, as a platform to do real-world work on Windows 8 feels utterly unusable. There's too much mystery meat navigation and the last thing I want is for my PC to force me into playing "hunt the app" every time I want to get something done.

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