ThinkPad T series T420s, and the T520, have been lauded for their battery life – up to 30 hours with a 9-cell battery slice. ThinkPad T series The ThinkPad T series is a line of laptop computers introduced by IBM in 2000. After the transfer of the consumer computer division in 2005, they were developed and marketed by Chinese technology company Lenovo. IBM introduced the T series as part of their ThinkPad brand in 2000. The laptop was meant to cater to users working with multiple networks and in different environments. This resulted in the development of the IBM Embedded Security Subsystem. From
ThinkPad W series are: The Lenovo W541 is essentially a ThinkPad W540 that featured the new-style keyboard but with a re-introduction of the classic ThinkPad trackpad design. The prior ThinkPad trackpad design featured in the W540 was abandoned. Rather than being a successor of any previous W-series model, the Lenovo W550s is a thinner Ultrabook variant of the W series. While a capable Ultrabook, when compared to the W541 and its predecessors, it offers less capability with only dual-core hyper-threaded Intel Broadwell Processors vs. the true quad-core processors of other models and has only two RAM slots. The ThinkPad W series was replaced