The Truth About Virtual RAM on Android

Android's virtual RAM feature — called RAM Plus (Samsung), Extended RAM (vivo), or Memory Extension (Xiaomi) — has been a source of controversy for years, with some believing it actually takes up internal storage. A detailed Reddit post and a recent discovery from SamMobile have laid bare the truth: virtual RAM (zRam) doesn't use storage by default, but manufacturers' vague explanations have led to confusion.

"Evague" explanation from the manufacturer

Virtual RAM — a popular feature on Android — is often misunderstood. When you enable it, your phone often warns you about memory usage. For example:

1. iQOO Neo9 Pro: " RAM can be dynamically expanded to 8GB. Part of the memory (ROM) will be utilized ".
2. Xiaomi Poco X3: " Add 1GB RAM by occupying memory. Use this feature only when the device has enough free space ".

These messages make users think that virtual RAM is 'eating' storage, but the truth is much more complicated. The RAM expansion feature relies on zRam — a kernel module that dedicates a portion of physical RAM to compressing data at a ~2:1 ratio, allowing more data to be stored in less space. By default, the feature does not interfere with storage, despite warnings from the settings menu to the contrary.

When zRam is full, the least used data is moved to the swap file on the storage — but only read/write at minimal performance to avoid wear. For example, when you enable "8GB+8GB Extended RAM" mode on Neo9 Pro, 2GB of memory is occupied after reboot. The swap file is only used if zRam reaches its limit.

This explains why the memory is still being taken up — suggesting the manufacturer isn't lying, just being transparent — and also confirms that the swap file isn't constantly being read/written. zRam trades off low CPU latency for data compression, allowing for smoother multitasking.

Next time you enable "Extended RAM" or "Memory Extension", keep in mind that:

1. This feature optimizes RAM performance without "stealing" your storage.
2. Swap file only activates if zRam is overloaded — a rare case with 8GB+ RAM on many modern smartphones.

Micah Soto

Update 26 May 2025