The ThinkPad X series is a line of notebook computers and convertible tablets produced by Lenovo as part of the ThinkPad family. The ThinkPad X series is traditionally the range best designed for mobile use, with ultraportable sizes and less power compared to the flagship ThinkPad T series. It was initially produced by IBM until 2005.
IBM announced the ThinkPad X series (initially the X20) in September 2000 with the intention of providing "workers on the move with a better experience in extra-thin and extra-light mobile computing." The ThinkPad X series replaced both the 240 and 570 series during IBM's transition from numbered to letter series during the early 2000s. The first X Series laptops were "slimmer than a deck of cards" and "lighter than a half-gallon of milk", despite the presence of a 12.1-inch Thin-film transistor (TFT LCD) display. These design values—thin and light—continued to be integral to the ThinkPad X-series laptops' design and marketing, 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 laptop styles include traditional ultraportables, as well as convertible tablet designs. According to Lenovo, the ThinkPad X-series laptops include low power processors, offer long battery life, and several durability features such as a Roll Cage (Magnesium Frame around the Display), magnesium alloy covers, and a spill-resistant keyboard but currently lacks a replaceable battery and upgradable RAM slots.
Battery configuration
| Main | M(x) | Main hot-swappable (max.cells)
 | Secondary | U | Ultrabay removable | 
|---|
| u | Ultrabay unremovable | 
| M(x) | Main removable (max.cells)
 | m(x) | internal (max.cells)
 "PowerBridge"
 | 
| m(x) | Main internal (max.cells)
 | S | Slice battery | 
| Laptop color codes | 
| 
| Processor   Socketed desktop processor   Socketed mobile processor   Soldered high power processor   Soldered standard power processor   Soldered low power processor   Soldered ultra low power processor Weight 
| 0.9 kg (2.0 lb) | Up to 0.91 kg |  
| 1.0 kg (2.2 lb) | 0.92–1.0 kg |  
| 1.1 kg (2.4 lb) | 1.01–1.1 kg |  
| 1.2 kg (2.6 lb) | 1.11–1.2 kg |  
| 1.3 kg (2.9 lb) | 1.21–1.3 kg |  
| 1.4 kg (3.1 lb) | 1.31–1.4 kg |  
| 1.5 kg (3.3 lb) | 1.41–1.5 kg |  
| 1.6 kg (3.5 lb) | 1.51–1.6 kg |  
| 1.7 kg (3.7 lb) | 1.61–1.7 kg |  
| 1.8 kg (4.0 lb) | 1.71–1.81 kg |  
| 1.9 kg (4.2 lb) | 1.81–1.91 kg |  
| 2.0 kg (4.4 lb) | 1.91–2.03 kg |  
| 2.1 kg (4.6 lb) | 2.04–2.14 kg |  
| 2.3 kg (5.1 lb) | 2.15–2.4 kg |  
| 2.5 kg (5.5 lb) | 2.41–2.75 kg |  
| 2.8 kg (6.2 lb) | 2.76–3.05 kg |  
| 3.1 kg (6.8 lb) | 3.06–3.42 kg |  
| 3.5 kg (7.7 lb) | 3.43–3.99 kg |  
| 4.0 kg (8.8 lb) | 4.0–4.99 kg |  
| 5.5 kg (12 lb) | 5.0–6.49 kg |  
| 7.2 kg (16 lb) | 6.5–7.99 kg |  
| 9.1 kg (20 lb) | 8.0–9.99 kg |  
| 10.7 kg (24 lb) | 10–11.99 kg |  
| 12.7 kg (28 lb) | 12–14.49 kg |  
| 14.5 kg (32 lb) | 14.5–17.99 kg |  
| 18.1 kg (40 lb) | 18–20.99 kg |  
| 21.7 kg (48 lb) | 21–23.99 kg |  
| 24 kg (53 lb) | 24–28.99 kg |  
| 29.5 kg (65 lb) | 29 kg and above |  
 | Screen resolution   4K or higher   1440p+ (WQHD,QXGA)   1080p+ (Full HD,UXGA)   Better than 768p (SXGA,SXGA+)   600p+ (SVGA,HD,XGA,HD+)   Up to 600p (VGA) Graphics   Dual standard socket graphics option   Dual proprietary socket graphics option   Standard socket graphics option   Proprietary socket graphics option   Soldered performance graphics option   Soldered midrange graphics option   Soldered mainstream graphics option   Soldered entry graphics option   Integrated entry graphics   Integrated basic graphics   |  Laptop storage combinations (excluding WWAN slot) 
| Level | PCIe 4.0 x4 | PCIe 3.0 x4 | PCIe 3.0 x2 | M.2 SATA | mSATA | 1.8" SATA | 2.5" SATA | 1.8" IDE | 2.5" IDE | 
|---|
 
|  | 2019 Not yet
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 | 2013 | 2013 | 2013 | 2009 | 2003 | 2003 | 1991 | 1988 |  
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|  | 1 |  Laptop memory 
| Amount | LPDDR5X | LPDDR5 | DDR5 | LPDDR4X | LPDDR4 | DDR4 | LPDDR3 | DDR4 | DDR3L | DDR3 | DDR2 | DDR | SDR | EDO | FPM | 
|---|
 
|  |  |  |  |  | dual channel |  | < dual channel | dual channel | < dual channel | dual channel | < dual channel | dual channel | < dual channel |  |  |  |  |  
| 2022 (laptops)
 | 2019 (laptops)
 | 2020 
 | 2017 | 2014 | 2014 | 2012 | 2014 | 2010 | 2007 | 2003 | 1998 | 1993 | 1993 | 1987 |  
| max memory = 512 GB | N/A | N/A | 512 GB | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A |  
| max memory = 256 GB | N/A |  | 256 GB (4 slots) | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A |  
| max memory = 128 GB | 128 GB |  | 128 GB | N/A | N/A | 128 GB (4 slots) | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A |  
| 64 GB ≤ max memory < 128 GB |  | 64 GB |  | N/A | N/A | 64 GB | N/A | 64 GB (2 slots) | 64 GB (4 slots) | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A |  
| 32 GB ≤ max memory < 64 GB |  |  |  | 32 GB | 32 GB | 32 GB | N/A |  | 32 GB | 32 GB (2 slots) | 32 GB (4 slots) | N/A | N/A | N/A | N/A | N/A | N/A | N/A |  
| 16 GB ≤ max memory < 32 GB |  |  |  |  |  | 16 GB | 16 GB |  | 16 GB |  | 16 GB | 16 GB (2 slots) | 16 GB (4 slots) | N/A | N/A | N/A | N/A | N/A |  
| 8 GB ≤ max memory < 16 GB |  |  |  |  |  | 8 GB |  |  | 8 GB |  | 8 GB |  | 8 GB | 8 GB (2 slots) | 8 GB (4 slots) | N/A | N/A | N/A |  
| 4 GB ≤ max memory < 8 GB |  |  |  |  |  | 4 GB |  |  | 4 GB |  | 4 GB |  | 4 GB |  | 4 GB | 4 GB (4 slots) | 4 GB (4 slots) | N/A |  
| 2 GB ≤ max memory < 4 GB |  |  |  |  |  | 2 GB (8 chips) |  |  | 2 GB |  | 2 GB |  | 2 GB |  |  | 2 GB | 2 GB | N/A |  
| 1 GB ≤ max memory < 2 GB |  |  | 1 GB (1 chip) | dual channel min | dual channel min | N/A |  | single channel min | 1 GB |  | 1 GB |  | 1 GB |  |  |  |  | 1 GB (4 slots) |  
| 512 MB ≤ max memory < 1 GB | N/A | N/A | N/A | single channel min | single channel min | N/A | dual channel min | half channel min | 512 MB (8 chips) |  | 512 MB (8 chips) |  | 512 MB |  |  |  |  | 512 MB |  
| 256 MB ≤ max memory < 512 MB | N/A | N/A | N/A | 256 MB (1 chip) | 256 MB (1 chip) | N/A | single channel min | 256 MB (1 chip) | N/A | single channel min | N/A | single channel min | 256 MB |  |  |  |  |  |  
| 128 MB ≤ max memory < 256 MB | N/A | N/A | N/A | N/A | N/A | N/A | 128 MB (1 chip) | N/A | N/A | half channel min | N/A | half channel min |  |  |  |  |  |  |  
| 64 MB ≤ max memory < 128 MB | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | 64 MB (1 chip) | N/A | 64 MB (1 chip) |  |  |  |  |  |  |  
| max memory < 64 MB | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A |  |  |  |  |  |  |  |