HP Compaq tc4200

The tablet PC market is heating up, with HP and IBM (under ThinkPad's new owner Lenovo) stepping into the fray with new models this summer. We'll have to wait a couple of months for the Lenovo, but HP's Compaq tc4200 is available now.

It's essentially the Compaq nc4200 notebook with a twist screen, which will suit large companies deploying a mix of notebooks and tablets. But convertibles bring both advantages and disadvantages. Typically more powerful than slates, they also benefit from a keyboard for desktop use. However, they're often heavier, and the single screen hinge is a mechanical weak point.

Hinge movement in the tc4200 is smooth, although the screen is free to move from side-to-side and HP hasn't added rubber stoppers at the corners of the chassis to prevent this. It lets the display lie closer to the base section in tablet mode, at the risk of stressing the hinge in notebook mode if handled roughly.

A clever mechanism holds the screen shut whether in tablet or notebook form. A magnet pulls the catch from the base as the lid closes, so there's nothing to snag when it's open. This doesn't provide much mechanical strength, but plastic lugs either side of the keyboard, with matching recesses in the lid, help to secure it.

The longer we used the keyboard the more we liked it. The spill-resistant board is firmly supported underneath, eliminating bounce, and the keys have a quality feel. HP has trimmed down some key sizes, but thankfully it's restricted to lesser-used keys such as backslash and the number '1' key, leaving normal typing unaffected.

There's also a trackpoint to complement the touchpad, but the latter's mouse buttons travel too far below the surrounding palmrest to be easily triggered with a thumb, so we tended to rely on the trackpoint instead. Handy volume controls lie above the keyboard, although we'd prefer a thumbwheel on the side that could be used in slate mode as well.

In slate mode, you pop the rather ordinary stylus out using a button in the display's bezel, which prevents accidental release when the lid's closed. Also on the bezel is an ambient light sensor and three symbols that can be activated with the stylus: screen rotation; the writing pane; and the Q menu, which controls a variety of hardware settings. Pen calibration is precise and, when carefully adjusted, doesn't suffer any significant misalignment, even at the screen's outer edges. There's a handy jog dial too, for scrolling through slide shows or large documents.

However, it's in slate mode that the convertible's weight disadvantage is noticeable. For a notebook, 2.1kg is admirable, but it starts to feel heavy after a short time. When looking under the bonnet, though, we see one of the convertible advantages. There's a 1.86GHz Intel Pentium M 750 inside, giving a good level of standard notebook power, and the latest 915GM Express chipset too. Our benchmarks recorded 1.75, proving there's no compromise on performance - and battery life is just as good, with the tc4200 powering on for five hours, 32 minutes under a light load with the screen dimmed. HP also sells a clip-on travel battery (£103 exc VAT) that you can run in parallel with the main battery for day trips from the office.

We also liked the screen. The 12.1in 1,024 x 768-pixel TFT lacked brightness at the top end, but the non-reflective coating is effective, notably improving readability. The screen also benefits from a strong backing inside the lid for protection when travelling. The general design and manufacturing standard is high, and HP backs the tablet with a reassuring three-year collect-and-return warranty.