Lenovo ThinkPad T420s - RAM Upgrade Guide
The Lenovo T420s laptop has two memory slots available for RAM upgrades. It can support a maximum of 8GB of memory. The type of RAM used in this model is DDR3 SDRAM, and it comes in a small outline dual inline memory module (SODIMM) format. For optimal performance, the recommended clock speed for the RAM is 1333MHz, which corresponds to the PC3-10600 standard.
Lenovo ThinkPad T420s Memory Specifications & Maximum RAM Capacity
| Specification | Value |
|---|---|
| Laptop Model | Lenovo ThinkPad T420s |
| Total memory slots | 2 |
| Maximum RAM | 8GB |
| Memory type | DDR3 SDRAM |
| Form factor | SODIMM (Small Outline Dual Inline Memory Module) |
| Recommended RAM clock speed | 1333MHz (PC3-10600) |
| Voltage | 1.35V - 1.5V |
| Number of pins | 204-pin |
FAQ about Lenovo ThinkPad T420s RAM
How much RAM can I put in a T420s?
Maximum is 8GB total. You've got 2 slots, so that's 2x4GB sticks. The system won't recognize anything larger than 4GB per slot.
What type of memory does the T420s use?
DDR3 SODIMM - the small laptop memory sticks. Make sure it's DDR3, not DDR3L or DDR4. Those won't work.
What speed RAM should I get for the T420s?
1333MHz (PC3-10600) is what you want. The system might accept 1600MHz sticks but they'll just run at 1333MHz anyway, so save your money.
Can I mix different RAM sizes in my T420s?
Yeah, you can do like 2GB + 4GB if you want. Just loses dual channel performance, but it'll work fine. Better to match them if possible though.
Is upgrading the RAM on a T420s difficult?
Pretty easy actually. Remove the battery, unscrew the RAM door on the bottom, pop out the old sticks, slide in the new ones at an angle then push down. Takes maybe 5 minutes.
Will any DDR3 SODIMM work in my T420s?
As long as it's regular DDR3 (not DDR3L) and 1333MHz or 1600MHz, you should be good. Stick to known brands though - had weird issues with super cheap generic stuff before.