Acer has jumped the gun at CES with a pre-event press conference this Sunday afternoon in Las Vegas. Amongst a handful of product announcements is this Aspire S5, alongside the Acer Aspire Timeline Ultra . The Aspire S5 is the world’s thinnest Ultrabook to date, measuring only 15mm at the widest point. With plenty more releases to come over the next few days this claim may not stand for long though; and with other Ultrabooks (like the Asus ZenBook) using tapering designs, it’s hard to judge like-for-like in terms of thinness anyway.

Arguments over dimensions aside the hardware itself is undeniably impressive, with a magnesium-aluminium alloy body. Despite its slenderness the whole thing felt very rigid and sturdy.

Here you can see the IO port open

The standout feature of the S5 is certainly its Magical I/O port – though the name is overegging the motorised flap, it’s certainly clever. Press a key to the right of the keyboard and the lower rear section of the laptop extends down revealing previously hidden ports. There’s a good selection too, with HDMI, USB3 and Thunderbolt. The latter can support very high-speed external storage (and very expensive too) or be used as a Mini DisplayPort.

The little button on the right opens the port bay, this also lifts the laptop slightly off the desk at the rear

At present the Magical I/O port makes a rather non-magical whirry-grinding noise as it comes up and down. Acer representatives said the sample wasn’t finalised, so there’s hope it will get quieter. We were also concerned that it didn’t seem to stop when obstructed, it gave our misplaced finger a nasty nip. We suppose that software could prevent the port from closing when a cable is plugged in, but Aver gave no indication of this.

The S5 has a claimed boot time of 1.5 seconds and also supports Acer Always Connect, which sounds a lot like the Active Standby Microsoft discussed for Windows 8 – where the laptop wakes periodically from sleep to update itself. That way everything is already up-to-date when you press the power button. Battery life wasn’t disclosed, though.

The keyboard lacked a little travel but otherwise felt OK. The cursor keys have been replaced by tiny versions to help save space though. The big trackpad below has no buttons, but instead clicks down in its entirety.

Specifications and pricing weren’t available, but based on the build quality and the I/O port we’d expect it to be towards the upper end of the scale. We look forward to getting a review sample when the S5 starts shipping in the vaguely defined Q2 of this year.