Ubuntu – Ubuntu 18.04 too slow


I migrated to Ubuntu 18.04 a week ago due my VPN needs, and it works perfectly except that the OS is too slow and I sometimes can't open any applications until I reboot.

My laptop has good hardware (a seventh-generation Intel Core i7 and 8 GB of RAM), but my memory utilization is 6 GB or more when I run Skype, Slack, and Firefox together.

Is this normal?

vmstat 10 4 output:

procs -----------memory---------- ---swap-- -----io---- -system-- ------cpu-----
 r  b   swpd   free   buff  cache   si   so    bi    bo   in   cs us sy id wa st
 7  0      0 898448  56344 3007108    0    0   148   215  420 1246 12  4 78  7  0
 7  0      0 887908  56376 3059492    0    0     1    68 4231 13951 33 10 56  0  0
 7  0      0 943000  56416 2996092    0    0     0   102 4199 14527 32 10 58  0  0
 3  0      0 934796  56448 3003276    0    0    23   103 4397 14711 34 10 55  1  0

Best Answer

High memory utilization is quite normal on a Linux system. Ubuntu is no exception. It uses unused memory for disk caching to increase system performance. You can find a good explanation with some further detail here.

Slow speed is often more a function of DE weight (gnome is heavy) than distribution version. LXDE and XFCE are very light and can make even low quality or somewhat obsolete hardware deliver acceptable performance.

Other things that can drastically reduce system speed are failing or poorly performing storage devices, dusty or otherwise compromised cooling systems can lead to overheat conditions that will cause modern processors to reduce speed in an attempt at self preservation.

The output of commands like dmesg and grep "error" /var/log/syslog can also provide clues as to what's going wrong in a system that doesn't perform as expected.

This is by no means a complete list, but it should give you some clues, and may very well lead you to new and more focused questions.

The memory leak bug you mention appears to now be squashed, However your vmstat output doesn't appear to indicate that you are effected by that bug.

According to your vmstat output your CPU is spending the majority of it's time idle, so the bottleneck isn't there. My best guess given the information available is either storage device or cooling system problems.

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