ThinkPad X series the presence of a 12.1-inch Thin-film transistor (TFT LCD) display. These design values – thin and light – continued to be a part of the ThinkPad X-series laptops even after the purchase of IBM’s Personal Computing Division by Lenovo. The first X Series ThinkPad released by Lenovo was the X41 in 2005. The ThinkPad X-series laptops from Lenovo were described by Trusted Reviews as combining an ultraportable's weight and form factor with a durable design. The X-series laptops include traditional ultraportables, as well as convertible tablet designs. According to Lenovo, the ThinkPad X-series laptops include low power processors, offer long
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