X1 Extreme Expansion Opportunities - No Soldered RAM in this X1 - Every single X1 Extreme will accept 4TB NVMe + 64GB DDR4 RAM whenever you are ready regardless of what it
Adding a Second NVMe SSD to a Lenovo ThinkPad X280 Using the WWAN Slot – PanicAcid.com
Productivity on the Go: Review of the Lenovo ThinkPad X280 Ultraportable Notebook - The Tech Revolutionist