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iPhone 18 Pro Max storage speeds vary by capacity
Hardware tests conducted by Homolab on the Bilibili platform indicate that higher-capacity models of the iPhone 18 Pro Max utilize different storage technologies than lower-capacity versions. While the 256 GB and 512 GB models use faster Triple-Level Cell (TLC) flash memory, the 1 TB and 2 TB models employ Quad-Level Cell (QLC) memory to manage costs and density.
To mitigate the slower native speeds of QLC, Apple has implemented a multi-layered caching architecture. This includes an ultra-fast SLC cache capable of approximately 3,000 MB/s, followed by a secondary TLC buffer at roughly 578 MB/s. However, under extreme, continuous write loads, once these buffers are exhausted, data is written directly to the QLC storage, causing speeds to drop significantly to between 25 MB/s and 79.4 MB/s.
Performance degradation becomes more pronounced as the device's storage fills. At 60% capacity, the effective size of the SLC cache shrinks, and tests showed QLC write speeds plummeting to as low as 1.1 MB/s during simulated total saturation. Additionally, the 1 TB model demonstrated a 38% slower performance in 4K random file read tests compared to the 512 GB variant.
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What the coverage asserts, and how many sources carry each claim.
- [● 2 SOURCES] At 60% storage capacity, the 1 TB model's QLC write speed can drop to as low as 1.1 MB/s. jablickar.cz · www.komputerswiat.pl
- [● 3 SOURCES] The SLC cache provides write speeds up to 3,000 MB/s. jablickar.cz · techmaniacs.gr · www.komputerswiat.pl
- [● 3 SOURCES] Apple uses a three-tier caching system for QLC models consisting of SLC, TLC, and QLC layers. jablickar.cz · techmaniacs.gr · www.komputerswiat.pl
- [● 2 SOURCES] The 1 TB and 2 TB iPhone 18 Pro Max models utilize QLC flash memory. techmaniacs.gr · www.komputerswiat.pl
- [● 3 SOURCES] The 256 GB and 512 GB iPhone 18 Pro Max models use TLC flash memory. jablickar.cz · techmaniacs.gr · www.komputerswiat.pl
- [● 3 SOURCES] When the SLC and TLC caches are exhausted, write speeds drop to between 25 MB/s and 79.4 MB/s. jablickar.cz · techmaniacs.gr · www.komputerswiat.pl
- [○ 1 SOURCE] The 1 TB model was 38% slower than the 512 GB model in 4K random file read tests. www.komputerswiat.pl
- [● 3 SOURCES] Tests conducted by Homolab on Bilibili reveal storage speed differences in iPhone 18 Pro Max models. jablickar.cz · techmaniacs.gr · www.komputerswiat.pl