I can confirm the same problem for me (however the system in question is actually Fedora 27, but no other online source provided a solution except for this bug report):
kernel: 4.10.10 SMP PREEMPT i686 (32bit) compiled with gcc_7.3.1 started with write speeds at around 180 MB/s and within minutes would slow down and stabilize at 3 MB/s # echo 3 > /proc/sys/vm/drop_caches did not work, but # sysctl -w vm.highmem_is_dirtyable=1 worked like a charm! I will try to see if I can test some of the other kernels as mentioned above (64bit, versions above 4.13) and see if those manifest the same issues. Thanks Norbert (nrbrtx)! -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1333294 Title: 32-bit kernel HDD slow write speed To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1333294/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs