---
title: iPhone 18 Pro Max SSD Slows Under Extreme Loads
description: "Via AppleInsider: The **iPhone 18 Pro Max** storage can be forced to run at very slow speeds under artificially extreme, sustained loads. You probably won't ..."
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url: https://headlinesbriefing.com/mobi/appleinsider/iphone-18-pro-max-ssd-slows-under-extreme-loads-bd40508c
sources:
  - GSMArena
  - Engadget
  - Android Central
  - MacRumors
  - 9to5Mac
  - AppleInsider
---

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### iPhone 18 Pro Max SSD Slows Under Extreme Loads

AppleInsider • September 21, 2026 at 9:39 AM ET

[×](/mobi?tab=appleinsider)

The **iPhone 18 Pro Max** storage can be forced to run at very slow speeds under artificially extreme, sustained loads. You probably won't ever see this. The internal storage of a smartphone needs to be fast for most tasks, especially when it comes to storing video footage from the cameras.

However, while most brief tasks enjoy this speed, it seems the new **iPhone 18 Pro Max** may have a limitation under extremely heavy loads. In an analysis from Bilibili channel **Homolab**, the type of storage Apple uses in the **iPhone 18 Pro Max**'s 1TB-capacity model can cause problems under extreme loads. In some situations, it can get extremely slow, like just about any SSD.

Apple uses quad-level cell (**QLC**) storage instead of triple-level cell (**TLC**) flash storage in its higher-capacity models. Under sustained testing, the 1TB storage speed reached a speed of **79.4MB/s**, and even hit **25.6MB/s** on occasion. This is normal, and expected, for the SSD in the iPhone.

The problem comes down to the use of **QLC** flash memory for storage over **TLC**. To get around these limitations, Apple included a small cache of single-level cell (**SLC**) SSD media, which handles brief write commands and acts as a buffer with the main storage capacity.

[Read original article](https://appleinsider.com/articles/26/09/21/iphone-18-pro-max-storage-hits-glacial-speeds-under-extreme-loads)

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You probably won't ever see this. The internal storage of a smartphone needs to be fast for most tasks, especially when it comes to storing video footage from the cameras. However, while most brief tasks enjoy this speed, it seems the new **iPhone 18 Pro Max** may have a limitation under extremely heavy loads. In an analysis from Bilibili channel **Homolab**, the type of storage Apple uses in the **iPhone 18 Pro Max**'s 1TB-capacity model can cause problems under extreme loads. In some situations, it can get extremely slow, like just about any SSD. Apple uses quad-level cell (**QLC**) storage instead of triple-level cell (**TLC**) flash storage in its higher-capacity models. Under sustained testing, the 1TB storage speed reached a speed of **79.4MB/s**, and even hit **25.6MB/s** on occasion. This is normal, and expected, for the SSD in the iPhone. The problem comes down to the use of **QLC** flash memory for storage over **TLC**. 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