Lenovo ThinkPad X1 Carbon 4th

Type 20FB Laptop, from 2016 28 hardware reports
Memory
Up to 8 GB
1 laptop-size slot
Battery
52 Wh
Reported by the batteries
SSD and charger
Coming next
Checked from separate sources
Upgradable

Yes. One slot, up to 8 GB seen working.

It takes LPDDR3-1866 laptop-size sticks (SO-DIMM).

Slots
1 SO-DIMM slot
Type
LPDDR3-1866 SO-DIMM
Most seen working
8 GB in two or more machines
Firmware says
20 GB maximum (often wrong, so we show what machines run)
How sure
25 of 28 reports show this layout
See 8 GB LPDDR3-1866 SO-DIMM on AmazonOpens an Amazon search for this exact spec.

Worked out from 28 hardware reports of this laptop. Sources and method. Updated 9 Nov 2026.

1 laptop-size slot
Illustration
Battery

Batteries in these laptops report 52 Wh.

That is the design capacity the batteries themselves report, and the label can read 1 to 3 Wh higher. Other pack sizes may have shipped, so check the capacity printed on yours before you order.

Lenovo ThinkPad X1 Carbon 4th battery on AmazonMatch the capacity and part number to the label on your battery.

From 28 battery readings. Sources and method. Updated 9 Nov 2026.

Illustration

Questions

Can I upgrade the RAM in the Lenovo ThinkPad X1 Carbon 4th?

Yes. One slot, up to 8 GB seen working. It takes LPDDR3-1866 laptop-size sticks (SO-DIMM).

What type of RAM does the Lenovo ThinkPad X1 Carbon 4th use?

LPDDR3-1866 laptop-size sticks (SO-DIMM).

How much RAM can the Lenovo ThinkPad X1 Carbon 4th take?

Machines in the reports run up to 8 GB. The firmware reports a maximum of 20 GB, a figure that is often wrong.

What battery does the Lenovo ThinkPad X1 Carbon 4th use?

Batteries in these laptops report 52 Wh, going by 28 reports. Other pack sizes may have shipped, so check the capacity printed on yours.

Is this my laptop?

Check the label on the bottom. It should say ThinkPad X1 Carbon 4th, and the type code starts with 20FB. Other type codes share this name: 20FC, 20FQ, 20FR.

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