Why is Kubuntu 22.04 much slower than Debian 11 with KDE?

Question

I recently switched from Windows 7 Ultimate to Kubuntu 22.04 LTS on my 10-year-old HP laptop. I love it for a lot of reasons, except for the performance. Compared to Windows 7 running on the same hardware, apps take about 50% longer to launch. Google Chrome and Firefox in particular run all four cores up to 100% in System Monitor, essentially locking up the OS. I can run Konquerer with the exact same tabs open and it requires a fraction of CPU resources. Discover is slow and crashy. I haven't installed anything exotic -- just a few desktop apps.

I tried 6 or 8 other KDE-based Linux distros on VirtualBox 7, and they seemed to suffer from the same issues. Finally, I tried Debian 11 Bullseye with KDE, and it seems to be a world of difference. Very snappy. It runs better in a VM than Kubuntu does as the host OS!

I can't see anything in Debian that's missing compared to Kubuntu. It required just a few extra tweaks.

My questions: Has anyone else had this experience? Am I missing anything if I switch from Kubuntu to Debian + KDE?

System:
  Kernel: 5.15.0-67-generic x86_64 bits: 64 compiler: gcc v: 11.3.0
    Desktop: KDE Plasma 5.24.7 Distro: Ubuntu 22.04.2 LTS (Jammy Jellyfish)
Machine:
  Type: Laptop System: Hewlett-Packard product: HP Pavilion 17 Notebook PC
    v: 0975100000405F10000620180 serial: <superuser required>
  Mobo: Hewlett-Packard model: 227F v: 77.26 serial: <superuser required>
    UEFI: Insyde v: F.12 date: 08/18/2014
CPU:
  Info: dual core model: Intel Core i5-4210U bits: 64 type: MT MCP
    arch: Haswell rev: 1 cache: L1: 128 KiB L2: 512 KiB L3: 3 MiB
  Speed (MHz): avg: 2397 high: 2401 min/max: 800/2700 cores: 1: 2397
    2: 2396 3: 2395 4: 2401 bogomips: 19155
  Flags: avx avx2 ht lm nx pae sse sse2 sse3 sse4_1 sse4_2 ssse3 vmx

Thanks!

MWB · Answer 1 · 2023-03-15T00:15:06.283

The major difference between Debian and Ubuntu is Snaps. Snaps package apps individually with all their dependencies and store them compressed. When you start a snap, those packages get uncompressed and mounted in RAM.

If, say, your system is using one version of Gtk, different Snaps could come with their own versions and they will all be taking up RAM space individually.

If you have high-end hardware, that may not be a big concern. But if you do not, the extra resources needed for Snaps might not be the resources that you can spare.

If you decide to remove Snaps from your Ubuntu system, this question discusses how.

Why is Kubuntu 22.04 much slower than Debian 11 with KDE?

1 Answers1