Lenovo Thinkpad T420 Memory Slots

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As part of the 2011 ThinkPad refresh Lenovo has updated the ThinkPad T420 notebook alongside other members of T Series. The new refresh brings the latest Intel Second Generation processors to the ThinkPad T420 as well as usability enhancements aimed at improving the user experience for corporate users.

16Gb (2X8Gb) Ram Memory Compatible with Lenovo Thinkpad T420 4177, 4178, 4180, 4236 Series by CMS Brand (A13) at Amazon.com 16Gb (2X8Gb) Ram Memory Compatible with Lenovo Thinkpad T420 4177, 4178, 4180, 4236 Series by CMS Brand (A13) Visit the Computer Memory Solutions Store 4.6 out of 5 stars 28 ratings. RAM modules take up precious space, so laptops are typically engineered with only two RAM slots, and both are usually occupied by existing memory when you buy it. This means that a laptop that comes from the factory with 4GB of memory, likely has two 2GB memory modules installed. To upgrade to 8GB, you can’t just buy 4GB of RAM. 2019 UPDATE: Recommended 2.5' SATA III SSD: are the upgrades I made to my Lenovo Thinkpad T420. I'm sure this voids the warranty.

ThinkPad T420 Quick Specs:

The ThinkPad T420 can be configured with the new Second Generation Intel Core i3, Core i5 and Core i7 processors, up to 8GB DDR3 RAM and up to a 320GB HDD or up to a 160GB SSD. The ThinkPad T420 notebooks can be configured with Lenovo Enhanced Experience 2.0 which, when used with Lenovo RapidBoot can get your computer started 20 seconds faster than the standard Windows 7 laptop.

The T420 can be configured with a Discrete NVIDIA NVS 4200M (1GB VRAM) GPU with Optimus technology that can automatically switch between the integrated and discrete GPU to provide peak performance without sacrificing battery life.

The 14.0″ display has a 1366×768 resolution as default, but there is the option to upgrade to an HD+ display with a 1600×900 resolution.

ThinkPad T420 Features:

The new ThinkPad T420 has a collection of improvements that end users and IT will appreciate including enhanced video chat and conference calling thanks to a new Conference Call Mode which listens to sounds in a complete 360 degree radius using the dual array microphones and the ability to dial it in with the Private Chat Mode. Users will also love that the keyboard noise is now suppressed so that they can take notes without deafening the other callers.


The ThinkPad T420 also gets a performance boost thanks to TurboBoost+ from Lenovo which makes use of efficient designs and enhancements on the standard Intel TurboBoost 2.0 to keep laptops in TurboBoost for longer so that users have extra power when they need it.

Also updated are several usability features including the ability to close your laptop and walk to another conference room without losing your WiFi connection. IT managers will like that the battery and docking solutions for the Lenovo ThinkPad T, L and W Series are all the same for easy use across the corporation.

ThinkPad T420 Battery Life:

The ThinkPad T420 is rated for 15 hours with the standard 9 cell battery, and can be extended to 30 hours using the T series slice battery which stacks on the bottom. Slice batteries add weight, but they don’t extend out the back of the notebook like many extended consumer batteries do.

Lenovo ThinkPad T420 Pricing and Availability:

The Lenovo ThinkPad T420 will be available on March 29th with a starting price of $779 along with the rest of the ThinkPad T, ThinkPad L and ThinkPad W lines.

ThinkPad T420 Gallery:


ThinkPad T420 Specs:

ModelThinkPad T420
Intel® Core™ i7-2620M (2.70GHz, 4MB L3, 1333MHz FSB)
Intel® Core™ i5-2540M (2.60GHz, 3MB L3, 1333MHz FSB)
Intel® Core™ i5-2520M (2.50GHz, 3MB L3, 1333MHz FSB)
Intel® Core™ i5-2410M (2.30GHz, 3MB L3, 1333MHz FSB)
Intel® Core™ i3-2310M (2.10GHz, 3MB L3, 1333MHz FSB)

Intel® Core™ i7-2620M (2.70GHz, 4MB L3, 1333MHz FSB)

Operating SystemGenuine Windows® XP Professional 32-bit

Genuine Windows® Vista Business 32-bit

Genuine Windows® Vista Home Basic 32-bit

Genuine Windows® 7 Home Basic 32-bit

Genuine Windows® 7 Home Premium 32-bit

Genuine Windows® 7 Home Premium 64-bit

Genuine Windows® 7 Professional 64-bit

Genuine Windows® 7 Ultimate 32-bit (Special Bid)1

Genuine Windows® 7 Ultimate 64-bit (Special Bid)1

Hard DiskChoice: 160GB (7200rpm)1

250GB (5400rpm/7200rpm OPAL1)

320GB (5400rpm/7200rpm)

4GB Solid State Flash Drive, Serial ATA1

Intel® 80GB Micro Solid State Drive, Serial ATA

128GB Solid State Drive, Serial ATA

Intel® 160GB Solid State Drive, Serial ATA

Memory / RAMChoice: Up to 8GB
RAM speed1333MHz
Memory TypeDDR3
Optical DriveDVD ROM Read-Only1 Multi Burner/DVD CD Multi Rec
KeyboardImproved ergonomic design, ThinkPad UltraNav multipointing system, including TrackPoint pointing device and larger multitouch touchpad with flush design, larger Esc and Delete keys, separate microphone and speaker mute buttons with LEDs, VoIP Fn+F6 hotkey combination, LEDs added to CapsLk key, power-on button and fingerprint reader
Graphics CardIntel® Integrated HD Graphics Discrete NVIDIA® NVS 4200M (1GB VRAM ) with Optimus™ Technology
Available Integrated CommunicationWWAN ,Bluetooth 2.1, WiMAX, WLAN
Supported WLAN CardIntel® Centrino® Advanced-N + WiMAX 6250 (Kilmer Peak) 2×2 AGN

Intel® Centrino® Ultimate-N 6300 (Puma Peak) 3×3 AGN

Intel® Centrino® Advanced-N 6205 (Taylor Peak) 2×2 AGN

Intel® Centrino® Wireless-N 1000 (Condor Peak) 1×2 BGN

ThinkPad BGN* (RealTek® – Stockton) 1×1 BGN

Supported WWAN CardIntel® Centrino® Ultimate-N 6300 (Puma Peak) 3×3 AGN

Intel® Centrino® Advanced-N 6205 (Taylor Peak) 2×2 AGN

Intel® Centrino® Wireless-N 1000 (Condor Peak) 1×2 BGN

ThinkPad BGN* (RealTek® – Stockton) 1×1 BGN

WebCamIntegrated 2.0 MP Camera
Microphonedual digital microphones
Warranty1-year Limited Warranty
Dimensions13.4in x 9.05in x 1.18in -1.20in

(340mm x 229.8mm x 29.9-30.4mm)

WeightsStarting at < 4.84lbs (2.24kg)
Display14.0″ HD (1366 x 768) (230 NITS)

14.0″ HD+ (1600 x 900) (230 NITS)

USB Ports2 USB ports
eSata Port1 eSATA port/USB2.0 Combo
Other ports and slotsDisplay Port

1 Always-On USB 2.0 with yellow marking

34mm Express Card slot and SD Card reader

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I recently purchased a used Lenovo Thinkpad T420 laptop to replace the Lenovo Thinkpad T400 I was previously using as my main platform for researching open-source network simulators and emulators. The T420 is a five-year old product but it offers all the ports and performance I need. Because it is well past its depreciation curve, anyone can purchase a used T420 for a very low price.

I wanted a computer that supports high-resolution external monitors so it required a DisplayPort output. I also wanted to expand the number of VMs I can run concurrently with adequate performance so I needed a processor that supports HyperThreading. I wanted to switch to the Ubuntu Linux distribution and the Ubuntu Unity desktop environment needs just a bit more processing power to run smoothly. The Lenovo Thinkpad T420 meets all these requirements.

Continue reading to learn more about the Lenovo Thinkpad T420, another excellent and inexpensive Linux platform.

The Lenovo Thinkpad T420

The Lenovo Thinkpad T420 is a business-class notebook produced in 2011 that was leased in large volumes by companies for use by their employees. Now, these companies are returning these computers to the leasors so Lenovo T420 laptops are available at used-computer re-sellers and on eBay at very low prices.

When purchasing a used Lenovo T420, you need to be aware of what you will get for your money. The Lenovo Thinkpad T420 was originally produced in many different configurations. When comparing prices, take into account the features added to the computer.

When looking for a used T420, I suggest you purchase a model with the 1600×900 LED screen. Other parts of the T420, such as the hard drive and memory, are easy to upgrade. Some models of T420 come with a discreet NVIDIA graphics chip, which is not important for most users so don’t pay extra for it. Some models offer a fingerprint reader, which is a convenience.

Upgrading memory on a Thinkpad 420 is very easy. When Lenovo installs the base level of memory in a Thinkpad, it only uses one memory slot so it is inexpensive to upgrade the laptop to 8GB by purchasing one more 4GB DIMM — and the second slot is very easy to access.

Lenovo Thinkpad T420 Memory Slots

Replacement parts for the T420 are still available and Thinkpads are made to be easily repairable. You can download the T420 maintenance manual from the Lenovo web site. For example, the T420 I purchased has a few keys on which the letters are fading. If I decide to replace these keys, I can find multiple online stores that sell replacement keys just by searching for “thinkpad T420 key replacement” on Google.

My T420

The T420 I purchased was a well-equipped model with the Intel i5-2540M processor, a 1600×900 HD+ LED screen, Intel HD Graphics 3000 and NVIDIA NVS 4200M discreet graphics with Optimus graphics switching technology, a fingerprint reader, a webcam, 4GB memory, and a 320 GB 5400 RPM hard drive. It also has four USB2 ports, a Firewire port, a VGA output, and a DisplayPort output that supports an external monitor with up to 2560×1600 resolution. It came with Windows 7 Professional already installed.

All this cost me just $280 in Canada (or US$200), so it was very inexpensive for a well-built computer that will last me two to three years.

Install Linux on a Thinkpad T420

I describe the Linux install process and the software I use on my computer setup page.

Ubuntu Linux works very well on Thinkpads so the installation should be painless and Ubuntu should automatically set up a dual-boot system if Windows is already installed on the laptop.

NVIDIA graphics in Linux on Thinkpad T420

Lenovo Thinkpad T420 Memory Slots 1tb

As mentioned above, the T420 I purchased has an NVIDIA NVS 4200M discreet graphics chip. In Windows, the laptop will switch between the Intel graphics and the NVIDIA graphics as required by programs running. Unfortunately, the graphics switching technology does not work well in Linux so we must do some extra configuration to enable manual graphics switching, or just disable the NVIDIA graphics in the BIOS settings.

By default, Ubuntu Linux uses the NVIDIA graphics chip if it is installed. This offers high performance but it uses up battery power a lot faster than the Intel graphics. To improve battery life, you may install the NVIDIA driver that will allow you to manually enable and disable the NVIDIA graphics chip so you can choose between performance and battery life.

NVIDIA Graphics and Windows

The T420 I purchased came with Windows 7. When I booted up Windows 7, it offered a free upgrade to Windows 10. I chose not to upgrade to Windows 10 because it is not clear if the NVIDIA Optimus graphics switching technology will be supported in Windows 10.

Lenovo does not officially support the T420 with Windows 10 so they will not provide updated Windows 10 drivers. Without the right drivers for the NVIDIA chip and for power management, battery life may be much shorter in Windows 10.

For now, I will keep Windows 7 so that the NVIDIA switchable graphics and Lenovo power management features continue to provide good battery life when I run Windows.


In the past five years, computer performance has been “good enough” for most activities. Open-source software, such as Linux, runs very well on older computer hardware and provides all the newest features and security updates. Today, most people may be well served by a computer that is four or five years old. These older, used computers are very inexpensive to purchase.

Lenovo Thinkpad T420 Ram Upgrade


I am very pleased with the performance of my used Thinkpad T420 laptop when running Ubuntu Linux. In two or three years, I will upgrade to a Lenovo T450 or X1 Carbon when those models are close to the same US$200 price point that the T420 is at today.

Lenovo Thinkpad T420 Memory Upgrade

I may never buy a new laptop computer again.

Lenovo Thinkpad T420s

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