After updating, the USB4 external hard drive experienced a significant drop in write speeds.

After the latest macOS security update, the write speed of my NVMe external drive enclosure with the ASM2464PD controller has significantly dropped from the original 3000MB/s to 60MB/s. What could be the reason for this? Under identical conditions, the same enclosure achieves around 1800MB/s on a Windows laptop with USB4 support. The SSD installed in this enclosure is TOPMORE ARIS which has a capacity of 2TB and uses the exFAT file system.

MacBook Pro 16″, macOS 15.4

Posted on Apr 12, 2025 6:16 AM

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After updating, the USB4 external hard drive experienced a significant drop in write speeds.

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