Lenovo ThinkPad T400 (7420) - RAM Upgrade Guide
The Lenovo T400 (7420) laptop supports memory upgrades through its two available memory slots. It can handle a maximum of 8GB of RAM. The type of memory used is DDR3 SDRAM, and it comes in a SODIMM format, which is a compact design suitable for laptops. For optimal performance, the recommended clock speed for the RAM is 1066MHz, often labeled as PC3-8500.
Lenovo ThinkPad T400 (7420) Memory Specifications & Maximum RAM Capacity
| Specification | Value |
|---|---|
| Laptop Model | Lenovo ThinkPad T400 (7420) |
| Total memory slots | 2 |
| Maximum RAM | 8GB |
| Memory type | DDR3 SDRAM |
| Form factor | SODIMM (Small Outline Dual Inline Memory Module) |
| Recommended RAM clock speed | 1066MHz (PC3-8500) |
| Voltage | 1.35V - 1.5V |
| Number of pins | 204-pin |
FAQ about Lenovo ThinkPad T400 (7420) RAM
How much RAM can I put in a T400?
The T400 maxes out at 8GB total. It's got 2 slots, so you can do 2x4GB sticks. That's the ceiling - the chipset won't recognize anything higher even if you try.
What type of memory does the T400 use?
It takes DDR3 laptop memory - the small SODIMM sticks. Make sure you get DDR3, not DDR2 or DDR4. The laptop RAM is about half the size of desktop memory sticks.
What speed RAM should I get for the T400?
Go with 1066MHz (also labeled as PC3-8500). The system might work with faster RAM like 1333MHz, but it'll just downclock it to 1066 anyway, so you'd be wasting money on the faster stuff.
Can I mix different RAM sizes in the T400?
Yeah, you can mix sizes like 2GB + 4GB if you want 6GB total. It'll work fine, though matching pairs (like 4GB + 4GB) might give you slightly better performance since it can run in dual-channel mode.
Do I need to match the RAM that's already installed?
Not really necessary. As long as it's DDR3 SODIMM at 1066MHz, mixing brands is fine. The system will run all the RAM at the speed of the slowest stick, so just make sure they're all the same spec.