The ROG Ally X ships with a 1 TB SSD, and a modern game library fills that quickly, so storage on the Ally X is a planning problem as much as a fault. The handheld has one microSD card slot that accepts cards up to 2 TB and supports UHS-II, which is up to three times as fast as UHS-I and noticeably better for load times. Games can be installed to the card from Steam by adding the card as a library drive, and the card should be formatted NTFS.
Most owners find a 512 GB or 1 TB card is the sensible size. When the SSD is genuinely full, the order is the usual one: uninstall games you finished, move others to the card, clear shader and launcher caches, and use Windows Storage to see what else is large.
Differential
Likely causes of “ASUS ROG Ally X handheld storage is full or nearly full”, and how to tell them apart
- 1
A large library on the SSD
What separates it Games fill the 1 TB drive
How to confirm Move games to the microSD card or uninstall finished ones
- 2
A microSD card in the wrong format
What separates it Steam does not offer the card, or the card is read-only
How to confirm Format the card as NTFS in Windows
- 3
A slow card
What separates it Games stutter or load slowly from the card
How to confirm Use a UHS-II card and check Steam's drive speed
- 4
Shader and launcher caches
What separates it Windows shows tens of gigabytes in temporary files
How to confirm Settings, System, Storage, Temporary files
- 5
Duplicate libraries
What separates it Games installed in two launchers
How to confirm Keep one copy per game
Before you touch a setting
Record this first — changing settings destroys the evidence
- The sizes of the five largest games and their drive
- The card brand, size and speed class
- Whether the card is formatted NTFS
- How much free space Windows reports
Try in this order
0 of 6 completedSee what takes the space
ReversibleSettings, System, Storage and each launcher's own storage list.
Format the card as NTFS
ReversibleIn Windows, right-click the card in File Explorer and format it as NTFS.
Add the card to Steam
ReversibleSteam, Settings, Storage, Add Drive, choose the card.
Move or install games to the card
ReversibleIn the Steam library, choose the game's Properties and Move install folder.
Clean temporary files
ReversibleSettings, System, Storage, Temporary files.
Plan the next purchase
ReversibleA 1 TB UHS-II card is the size most owners settle on.
Model-specific
What is true of this model and not of its siblings
- The slot
- One microSD slot supporting UHS-I and UHS-II cards up to 2 TB.
- Why NTFS
- Windows games need NTFS permissions that exFAT lacks, so the format matters for installing games.
Stop boundary
When this stops being a self-service repair
- !If the SSD reports errors in Windows, back up and contact ASUS
- !If a new card is not recognized in the slot, try another card before assuming a slot fault
- !If Windows runs out of space and updates fail, free several gigabytes first
Evidence ledger
Sources behind this answer
MicroSD slot, UHS-II speeds and sizes for the Ally X.
ASUS's guide to installing games on the microSD card.
Owners installing games to the card.
Specifications of the ROG Ally and Ally X.
Exact questions
Common questions
How much storage does the ROG Ally X have?+
A 1 TB SSD, with one microSD slot that takes cards up to 2 TB.
Which microSD card should I buy?+
UHS-II cards are up to three times faster than UHS-I; owners often choose a 512 GB or 1 TB SanDisk Extreme.
Why does Steam not show my card?+
It needs to be formatted NTFS and added under Storage, Add Drive.
Will games load slower from the card?+
A good UHS-II card is close to the SSD for most games; UHS-I is slower.