Guaranteed compatible upgrades for:

IBM/Lenovo ThinkPad T420

System Specifications
Maximum Memory:
  • 8GB (Lenovo official)
  • 16GB (Confirmed by many of our customers)
  • 2 Sockets
Standard Memory:
  • 2 GB (Removable) or
  • 4 GB (Removable)
  • Intel Core i7 Intel QM67
  • Intel Core i5 Intel QM67
Bus Architecture:
  • Flash - SDXC; SSD - SATA 2.5-inch 7mm; USB
Mfr's System P/N's:
  • 4177-xxx; 4178-xxx; 4180-xxx; 4236-xxx
Upgrade Path:
  • Virtually any configuration up to 16GB can be reached using any combination of 2,4 and 8GB modules.
  • Thanks to customer Gary M.
  • from IBM GSA for confirming that 2x8GB modules are compatible in the i5 and i 7 versions of the Lenovo T420 machine, allowing a whopping 16GB installed RAM.
  • All memory modules shown on this page are guaranteed compatible.