I currently own a Lenovo Y50 (Intel Core i7-4710HQ, Windows 10 Pro 64-bit) which contains 2 RAM modules of 8GB DDR3 PC3-12800 at 1600 Mhz. I want to buy a Thinkpad X220 or a Thinkpad T420 which both come pre-installed with Windows 7 Pro 64-bit, Intel Core i5-2520M, and a 4 GB DDR3 PC3-10600-1333 SODIMM.

Is it possible to take 8GB card from my Y50 and install it in the Thinkpad (X220 or T420), or will I run into compatibility issues?


It will work on the T420 but the RAM will be mismatched, and will run at the slower rate. Not sure about the X220 as there is several variants and it depends on which variant for the maximum ram.

EDIT: Whoops my bad looks like it will work on the X220 too, I read the specs wrong, but once again will be mismatched.

  • so the cons of mismatch rams is the thinkpad will run at slower rate? I should buy an identical RAM then?
    – dude
    Nov 3 '16 at 5:50
  • You should always buy matching ram if given the choice, but it isn't the end of the world...
    – TheXed
    Nov 3 '16 at 5:51
  • This answer should quote and link to the specifications because currently the other answer says something entirely different. I just happen to know it's correct which is the only reason I won't be withholding the upvote
    – Ramhound
    Nov 4 '16 at 0:08

The T420 and also the X220 will both accept 16GB of RAM (2x8 GB) 1*. 8GB+4GB also works. When mismatching RAM speeds, the RAM will run at the lowest speed. So, if you combine the 1333 MHz, 4GB, and 1600 MHz, 8GB module, they will run at 1333 MHz.

However, ideally, you should not transfer just one of the 8GB RAM sticks to your new laptop, but you should take both RAM modules from the Y50, and move them to your thinkpad. This way you have two identical RAM modules, which means you won't run into compatibility issues, and the RAM will run in dual-channel mode (which is significantly faster than single-channel mode).

*Note that the manufacturer specification says otherwise (it states max 8 GB ram). However, this is related to the max spec the T420 and X220 were originally sold with, not the actual maximum the hardware can take.

  • I felt the part in italic was vital information missing from the other answer. Therefore I decided to post a new answer.
    – BramMooij
    Nov 14 '16 at 11:02

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