[Bug 247964] Low read throughput on Sandisk Extreme external SSD
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Date: Mon, 20 Sep 2021 08:14:59 UTC
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=247964 Gary Jennejohn <gljennjohn@gmail.com> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |gljennjohn@gmail.com --- Comment #2 from Gary Jennejohn <gljennjohn@gmail.com> --- (In reply to Tom Jones from comment #0) You don't state which USB version you're using, but based on the transfer speeds it must be USB3. Not all USB3 ports/external enclosures are created equal. Is it USB3.0, USB3.1 or USB3.2? You don't state which USB3 versions your various computers support. For example, my FreeBSD box supports USB3.1 Gen 1 and, using the dd values you provide, I get a transfer rate of 378MB/s from a 1TB Samsung SSD 870 EVO (when I plug it in the USB stack reports 400MB/s transfers). When I plug this SSD into a Linux server, which only has USB3.0 support, I get only a 205MB/s transfer rate, while using the equivalent Linux dd command. So, don't blame FreeBSD alone. The USB3 hardware plays a big role in transfer rates. Note that the Linux server has a AMD 6-core 3.2GHz CPU and the FreeBSD box has a Ryzen 7 3700X. But the CPU shouldn't a bottleneck for USB transfers. -- You are receiving this mail because: You are the assignee for the bug.