Register for your free ZDNet membership or if you are already a member, sign in using your preferred method below.
Lenovo's T-series ThinkPads are designed to offer mobile professionals an appealing combination of performance and portability, wrapped up in the familiar durable ThinkPad design. The slimline 14in. T420s features Sandy Bridge processors and optional dual-mode integrated/discrete graphics, along with additions (under the banner Enhanced Experience 2.0 for Windows 7) such as rapid boot-up and shutdown. As with all ThinkPads, there's also a veritable arsenal of ThinkVantage Tools that help to keep the system secure and up-to-date.
The black-clad T420s looks every inch a ThinkPad, its standout visual features being the 14in. 1,600-by-900-pixel screen (which is LED-backlit and pleasingly non-glossy) and the traditional (non-isolation-style) keyboard.
The ThinkPad T420s is a 14in. notebook for business users with traditional tastes
The T420s is also noticeably slim for a full-featured business notebook at just 2.1-2.59cm, while the footprint, at 34cm wide by 23cm deep, means it should fit comfortably into most laptop bags. Sturdy construction and a solid two-point screen clasp should keep safe and sound in transit.
There's little flex in the lid section, and the keyboard feels admirably firm when you're typing. The system weighs a very manageable 1.78kg with an optical drive in the modular bay (as in our review unit), and the 90W power brick is reasonably compact.
We've used plenty of 'modern', MacBook-imitating isolation-style keyboards, and some (including those on Lenovo's own ThinkPad Edge series) are perfectly usable. But given the choice, we'd select the traditional ThinkPad keyboard, as seen on the T420s, every time. In terms of feel and layout, it simply cannot be beaten, in our opinion. There's no backlight, but you do get the Fn+PgUp-toggled ThinkLight that shines down from the top of the lid to help you work in dimly-lit conditions.
No 'chiclet' keys here, just nicely sculpted contiguous keys with plenty of travel on a rock-solid base
We've also used plenty of pointing sticks from other vendors, but few compare to those from its inventor. You get three buttons with the trackpoint (right and left mouse, plus scroll), and two with the stipple-surfaced touchpad, which has built-in vertical and horizontal scroll zones. The wrist-rest area has a fingerprint reader on the right-hand side, above the ThinkPad logo.
Our review sample of the ThinkPad T420s was powered by Intel's quad-core Core i7-2640M processor running at 2.8GHz (3.5GHz with Turbo Boost), supported by 4GB of DDR3 RAM. Up to 8GB of memory is supported, by filling both DIMM slots with 4GB RAM modules. A more affordable Core i5-2520M-based system is also available on Lenovo's UK web site, and you can customise the detailed configuration of both models.
The review unit was equipped with both discrete and integrated graphics, in the shape of Nvidia's NVS 4200M GPU with 1GB of dedicated DDR3 video memory and Intel's CPU-integrated HD Graphics 3000, which can dynamically command between 64MB and 1,696MB of system memory for its purposes. The NVS 4200M supports Nvidia's Optimus technology, which automatically switches between discrete and integrated graphics according to the workload, maximising battery life by not using a high-power GPU for low-end tasks.
Storage comes in the form of a fast, low-power 160GB Intel solid-state drive (SSD). This is an expensive option, and you can specify lower-capacity 128GB SSD for £79.80 (ex. VAT) less, or a 320GB, 7,200rpm hard drive for £214.12 (ex. VAT) less.
Connectivity options are excellent, our review sample not only featuring dual-band Wi-Fi (802.11a/b/g/n) and Bluetooth (3.0), but also HSPA mobile broadband (Ericsson F5521gw). Among the ThinkVantage Tools you'll find a Mobile Broadband Activate utility to set the connection when you insert your SIM. There's Gigabit Ethernet for wired networking too, of course.
You get a reasonable selection of ports and connectors on the T420s, but many users will want to add a port replicator or a docking station for extra features and in-office convenience.
The left-hand side has a USB 2.0 port and a 34mm ExpressCard slot, while the right-hand side is taken up mostly by a modular Ultrabay, fitted with an optical drive in our review unit. If you want the full claimed 10-hour battery life, you can replace the optical drive with a second 3-cell Ultrabay for an extra £68.40 (inc. VAT) to complement the system's primary 6-cell battery.
At the back, from left to right, there's an RJ-45 (Ethernet) port, a USB 3.0 port, a sleep-and-charge USB 2.0 port, a DisplayPort and a 15-pin VGA port.
If you want to keep network and external monitor connections in place in the office, a ThinkPad Port Replicator Series 3 with Ethernet, four USB 2.0 ports and a VGA connector will cost you £107.35 (ex. VAT) extra. A Mini Dock Series 3 with Ethernet, six USB 2.0 ports, VGA, DVI and DisplayPort connectors, plus a pair of audio jacks costs £178.60 (ex. VAT).
Other noteworthy features include a 720p HD webcam and a dual array microphone in the top screen bezel, and a pair of stereo speakers flanking the keyboard. These can be configured using the Communications Utility in ThinkVantage Tools, which includes useful settings such as microphone optimisation for single or multiple voices, keyboard noise suppression and single or multiple audio streams (over speakers and headphones).
Performance & battery life
Lenovo sets great store by the speed with which the ThinkPad T420s boots into Windows 7, claiming this can be achieved "in as fast as 10 seconds". Our review sample didn't show such eagerness to get Windows going, but booted up in a perfectly acceptable 30 seconds on average. It was quicker to exit Microsoft's OS though, taking just under 10 seconds to shut down.
WEI (Windows Experience Index) scores for the ThinkPad T420s ranged between a middling 4.7 (out of 7.9) for Graphics (Desktop performance for Windows Aero) and an impressive 7.5 for Primary hard disk (Disk data transfer rate). In between came Memory (RAM) (Memory operations per second) with 5.9, Gaming Graphics (3D business and gaming graphics performance) with 6.2 and Processor (Calculations per second) with 7.1.
Although the graphics subsystem delivers relatively low WEI scores compared to those for processor and primary hard disk (SSD in this case), bear in mind that the relatively undemanding WEI tests will be hitting the integrated Intel HD Graphics 3000 rather than the discrete Nvidia NVS 4200M GPU, which will kick in under Optimus when the graphical going gets tougher. In two weeks of general 'knowledge worker' use, we found the T420s admirably responsive.
Lenovo claims "up to 10 hours" of battery life for the ThinkPad T420s, when equipped with the primary 6-cell Li-ion battery and a second 3-cell Ultrabay battery. We didn't have the latter, which is a £57 (ex. VAT) option. To test the system's longevity with just the primary battery, we measured the system's average power consumption under idle and workload conditions, using a Voltcraft VC940 Plus multimeter. Dividing the resulting figures into the 6-cell battery's 44Wh capacity gives us estimates for battery life.
We tested the power consumption of the T420s under the Maximum Performance and Maximum Battery Life power plans, both idling at the Windows 7 desktop and performing a demanding workload (Cinebench 11.5's CPU test). Our battery life estimates ranged between 3 hours 19 minutes and 51 minutes, suggesting that Lenovo's battery life claims are optimistic and that you'll need that additional Ultrabay battery to get anything approaching a day's work from this notebook without a power socket to hand.
Much of the ThinkPad's design — and particularly the excellent keyboard — is traditional, but it packs plenty of up-to-date specs too: Core i7 CPU, hybrid discrete/integrated graphics, solid-state drive, USB 3.0 and a high-quality multimedia subsystem. All this makes for an expensive notebook, but it's one we're happy to recommend.