ThinkPad R series
Dropping the A series, IBM introduced a mainstream budget line of ThinkPads in the R series. The RXXe series lacks some of "normal" RXX series features like stereo speakers, touchpad, hot-swappable CD/DVD drive, docking connector and some other things. They also usually feature slower CPU like Intel Celeron (but in newer models also slower Intel Core processors). ACPI functions in modern RXX-e models are just as well supported in Linux as they are for the regular RXX models.
Starting from R61, the R series ThinkPads feature the same chassis (including RollCage) as the T series making them virtually indistinguishable from each other.
ThinkPad T series
As successor of the 600 series, the T series became IBM mobile productivity line. Usually leading the ThinkPad range in technology, innovation and price, the T series was intended for the travelling businessman - comparatively more stylish, functional, and rugged machines; and easy to disassemble for repair or upgrades. T series ThinkPads are clad in black non-slip rubber with embedded glitter. The case lid has tabs along the edge that interlocks with depressions in the lower case when closed, to reduce case flexing.
ThinkPad T2x series
The ThinkPad T2x models (T20, T21, T22, T23) were Intel Mobile Pentium III-M based, sub-5 lb (2.3 kg) class machines. These machines typically had 14.1 inch XGA screens, S3 Savage graphics chips and Cirrus Logic sound chips. The T2x series introduced the UltraBay 2000 optical drive bay and titanium-reinforced screen lids. With the T23, an internal WiFi antenna became available, so WiFi miniPCI cards could be used. Also the T23 was the first ThinkPad featuring an UltraBay Plus drive and Embedded Security Subsystem.
ThinkPad T3x series
The T3x series only saw one model, the T30. Powered by a Intel Mobile Pentium 4-M and a Radeon 7500 graphics chip with 16 MB of discrete video memory, the T30 was available with 14.1 inch XGA or SXGA screens. The T30 introduced the UltraNav touchpad and integrated Bluetooth among ThinkPads. Other features include the Embedded Security Subsystem, Ultrabay Plus drive, integrated Wireless LAN. The shell is titanium reinforced composite. The whole package was a bit heavier and thicker than both the T2x and the T4x series.
ThinkPad T4x series
Includes the T40, T41, T42, T43, and associated "p" series (for "performance"; e.g., T43p). A typical T4x weighs 2.2 kg (4.9 lb), slightly less than the 600 series, and features an Intel Pentium M (Dothan) Processor, a 14.1 or 15 inch LCD (XGA or SXGA+), an integrated GPU (Intel Graphics Media Accelerator 900) or a discrete GPU (ATI Mobility Radeon 7500, 9000, X300, ATI Mobility FireGL 9000, FireGL 9600, FireGL T2 and FireGL V3200), and a hard drive ranging in size from 30 to 100 GB with the Active Protection System to protect the hard drive (T41 and later models). "p" (mobile workstation) models are also available with a 14" SXGA+ or a 15 inch UXGA FlexView display with wide viewing angle and high density IPS technology with resolutions up to 1600x1200. These 15 inch display models weigh slightly more than their lesser brethren, with optical drive and battery, at 2.7 kg (5.9 lb). Some T42 and T43 models feature a biometric security system with Integrated Fingerprint Reader.
ThinkPad T6x series
ThinkPad T60 contained the Intel Core Duo (Yonah). It was paired with either a ATI Mobility Radeon X1300 or x1400 or with an ATI Mobility FireGL V5200 for the performance model. The T60 was also the first of its kind to support Wireless Wide Area Network (WWAN) out of the box if the option was selected.
The ThinkPad T60 refresh contained the Intel Core 2 Duo (Merom). It gave a processing speed of up to twenty five percent faster than the Yonah and introduced EM64T into the mobile realm. It was paired with either a ATI Mobility Radeon X1300 or x1400 or with an ATI Mobility FireGL V5250 for the performance model.
ThinkPad T61 features the Santa Rosa chipset, in addition to the existing Intel Core 2 Duo (Merom). The designers found it prudent to move from an ATI based Mobility Radeon to NVIDIA's Quadro NVS series discrete video processors. The move also marked a more aggressive shift to the wide screen format. Introductory T61 models only shipped with a wide screen. In addition, the designers added a Roll Cage for the screen to decrease the likelihood of damage in the event of a fall. Finally fan blades were overhauled to decrease fan noise and temperature.
ThinkPad X series
ThinkPad X12x series
X121e with Intel i3 or AMD CPUs, appeared 2011.
ThinkPad X2x series
Intel Mobile Pentium III with ATI Rage Mobility M (X20, X21) or Intel Mobile Pentium III-M with ATI Mobility Radeon 7000 (X22, X23, X24), sub-4 lb machines. Contained processors ranging from MPIII 500 MHz to PIII-M 1+ GHz. 12.1 inch XGA screens. Used miniPCI form factor cards, which supports modem and/or ethernet. With the X22 and later machines, provisions for wireless networking support are built into the chassis. UltraBay 2000 optical drive support can be fitted via the UltraBase X2 portable docking station option, and extended batteries can give the series a 5 hour running time.
ThinkPad X3x series
Intel Mobile Pentium III-M with Intel Graphics Technology (X30) or Intel Pentium M (Banias)/(Dothan) with ATI Mobility Radeon 7000 (X31, X32), 12.1 inch XGA screens, IrDA, FireWire, Compact Flash card slot. No built-in optical drive. Like the X2x series UltraBay Plus optical drive support can be fitted via the UltraBase X3 portable docking station option. As the UltraBase X3 can take the same battery as the notebook, the running time can be increased to amazing 10 hours.
ThinkPad X4x Series
A continuation of the lightweight X series. Weighting in at 1.2 kg (2.7 lb), the lightest X41 is 25% lighter than its predecessor, the X31. Part of the X4x series, the X41 Tablet is the first Tablet PC (convertible) ThinkPad. They also get UltraBay Slim optical drive support via the UltraBase X4 portable docking station option, but it is not compatible with the X41 Tablet.
ThinkPad X6x Series
Later, X61, X61s and X61 Tablet appeared. These ThinkPads are now migrated to the new Santa Rosa chipset, in addition to the existing Intel Core 2 (Merom) platform and has some design improvements. The X61 features full-blown Core 2 Duo processors, X61s and X61 Tablet can be configured only with low-voltage variants. In many benchmarks, the X61 proved, that it can be as fast as ThinkPad T61 with same configuration.
Unlike T61 and R61, the X61 series aren't available with widescreen display option.
ThinkPad E or Edge Series
This Series, originally introduced in early 2010 with the 13"(withdrawn), 14" and 15" models, are billed to "reflect a new progressive and strikingly clean appearance while retaining ThinkPad durability and reliability. For example, the laptops include spill-resistant keyboards and value-added ThinkVantage Technologies like the Active Protection System and Rescue and Recovery."
Complete product details of current (not withdrawn) Edge Series devices can be found in the PSRef for Lenovo ThinkPad Edge Notebooks
Needs additional info and history added for each of the sub-categories below
ThinkPad Edge 14" and 15" Series
ThinkPad Edge E220s
The only Edge product in this series so far is the E220s
ThinkPad Edge E4xx Series
ThinkPad Edge E5xx Series
ThinkPad Edge Twist
The Edge Twist is a bit of an odd member, as it is the only "convertible" one of the E or Edge series, and it's model name (S230u) does not begin with the usual "E". It's also the only one with a Multitouch capable display, nicely protected with "Gorilla Glass".
ThinkPad 200 series
The 200 series (220, 230, 235, 240 and their various sub series) was a subnotebook series. This means they were extremely small and light crossovers between notebooks and PDAs. The series ended with the 240X. With the changing from the numeric to the alphanumeric naming scheme in 2000, IBM stopped developing subnotebook class ThinkPads. Only in the Asia-Pacific only S series did in find a rather short revival.
ThinkPad 300 series
The 300 series (300, 310, 350, 360, 365E, 380, 385ED, 390 and their various sub series) was a long running value series starting at the Intel 386SL-33 going all the way to the Intel Mobile Pentium III. The ThinkPad 300 was also produced for IBM by Zenith Data Systems. They were a bit large and slower than the more full featured models but offered a less expensive ThinkPad. The successor of this series is the R series.
ThinkPad 500 series
The 500 series (500, 510Cs, 560, 570 and their various sub series) were the main line of the ultraportable ThinkPads. Starting with the IBM 486BL-25 Blue Lightening to the Intel Mobile Pentium III, these machines had only a hard disk onboard. Any other drives were either external or available in the respective Docking Solutions. Unique feature of this series: fan-less systems. The successor of the 500 series is the X series.
ThinkPad 600 series
The 600 series (600, 600D, 600E and 600X) are the direct predecessors of the T series, and are legendary for their portability and sturdy construction. Most 600 series models packed a 13.3 inch LCD, Intel Mobile Pentium II or Intel Mobile Pentium III processor and full sized keyboard into a package weighing roughly 2.3 kg (5 lb). The UltraSlimBay was introduced with the 600 series. IBM was able to create this light, fully featured machine by using lightweight but strong carbon fibre composite plastics.
ThinkPad 700 series
The 700 series (700, 701C, 730T, 750, 755C, 760E, 765D, 770 and their various sub series) were the cutting edge Intel-based ThinkPads. They featured the best screens, largest hard drives and fastest processors available at the time.
ThinkPad 800 series
The PowerPC ThinkPad series, (800, 820, 821, 822, 823, 850, 851, 860) were unique in that they ran on the PowerPC architecture, and not the x86 architecture. They all used the IBM PowerPC 603e CPU. The 800 may have used a 603, and it is unclear if the 800 was experimental or not. All units used SCSI 2 instead of IDE. The units are believed to have all been extremely expensive, as the 850 cost upwards of $12,000 USD. The 800 series can run Windows NT 3.5 (probably 4.0 as well), OS/2, AIX 4.14, Solaris Desktop 2.5.1 PowerPC Edition and Linux.
The IBM TransNote was a pen based PC in a notebook. Data could not only be entered through keyboard, TrackPoint and TouchScreen, but also through a unique paper notepad with integrated digitizer which was produced in cooperation with Cross AT. This ThinkPad expanded on IBM's previous pen based notebooks (360P(E), 730T(E), and 755(P).
ThinkPad A series
The A series was developed as an allround productivity machine, equipped with hardware powerful enough to make it a desktop replacement. Hence it was the biggest and heaviest ThinkPad series at its time, but also had features not even found in a T series of the same age. The A series was dropped in favour of the G series and R series.
ThinkPad G series
The G series consists of only two models so far, the G40 and G41. Being large and heavy machines, equipped with powerful desktop processors, this line of ThinkPads is consequently specialised in serving as a desktop replacement.
ThinkPad i series
The i Series introduced the ThinkLight and were also the first notebooks equipped with Wireless LAN. Some types from the i Series allow playing music CDs without turning on the computer.
ThinkPad S series
ThinkPad Z series
The widescreen ThinkPad build to offer the ultimate multimedia experience. Internal similar to the T series, but they have a widescreen and are available with a Titanium Special Edition Cover on selected models. This was the first ThinkPad series completely developed by Lenovo. This series was discontinued as the T series are available with widescreen displays.
ThinkPad Z60x Series
The first widescreen ThinkPads, internal similar to the T4x series, but they are available with 14" (Z60t) or 15.4" (Z60m) widescreens (some with optional MaxBright-technology). Travel weight starting at 4.1 lb and they are less than 1.1" thin. They are the first ThinkPads completely developed by Lenovo.
ThinkPad Z61x Series
Second generation Z series, upgraded to the internal technology level of the T60 series ThinkPads.
Adding a new series
Please refer to Adding a new ThinkPad series or category to ThinkWiki for instructions on how to add a new ThinkPad series to ThinkWiki.