Hello to all, hoping to post in the right forum ...
My system :
Debian Buster 64bits CPU: Intel i5-2400 (4) @ 3.400GHz GPU: NVIDIA GeForce GT 440
Memory: 1788MiB / 7958MiB Kernel: 4.14.0-3-amd64
Qt: 5.9.2 - KDE Frameworks: 5.42.0 - kf5-config: 1.0 - plasmashell 5.12.2 Applications 17.08.3

Kde5 takes very looong time (~2min) from login to Desktop ready.
Already tried some workaround like disable splash Screen and set "start with empty session".
No success.
Debian Buster on Laptop is not showing this issue.
Here I can put a comparison file from the .xsession-errors files from the two computers
Thanks for anyone giving hints

Laptop login starts:
Xsession: X session started for farina at Sat Mar 3 12:08:26 CET 2018

Desktop login starts:
Xsession: X session started for farina at Sat Mar 3 11:31:27 CET 2018

dbus-update-activation-environment: setting DBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/1000/bus
dbus-update-activation-environment: setting DISPLAY=:0
dbus-update-activation-environment: setting XAUTHORITY=/home/farina/.Xauthority
localuser:farina being added to access control list
dbus-update-activation-environment: setting GTK_MODULES=gail:atk-bridge
dbus-update-activation-environment: setting QT_ACCESSIBILITY=1
dbus-update-activation-environment: setting CLUTTER_IM_MODULE=xim
dbus-update-activation-environment: setting LANG=en_US.UTF-8
dbus-update-activation-environment: setting DISPLAY=:0
dbus-update-activation-environment: setting PAM_KWALLET5_LOGIN=/run/user/1000/kwallet5.socket
dbus-update-activation-environment: setting USER=farina
dbus-update-activation-environment: setting DESKTOP_SESSION=/usr/share/xsessions/plasma
dbus-update-activation-environment: setting QT4_IM_MODULE=ibus
dbus-update-activation-environment: setting PWD=/home/farina
dbus-update-activation-environment: setting HOME=/home/farina
dbus-update-activation-environment: setting QT_ACCESSIBILITY=1
dbus-update-activation-environment: setting XDG_SESSION_TYPE=x11
dbus-update-activation-environment: setting XDG_SESSION_DESKTOP=KDE
dbus-update-activation-environment: setting GTK_MODULES=gail:atk-bridge
dbus-update-activation-environment: setting SHELL=/bin/bash
dbus-update-activation-environment: setting XDG_SESSION_CLASS=user
dbus-update-activation-environment: setting XDG_SEAT_PATH=/org/freedesktop/DisplayManager/Seat0
dbus-update-activation-environment: setting QT_IM_MODULE=ibus
dbus-update-activation-environment: setting XMODIFIERS=@im=ibus
dbus-update-activation-environment: setting IM_CONFIG_PHASE=1
dbus-update-activation-environment: setting XDG_CURRENT_DESKTOP=KDE
dbus-update-activation-environment: setting GPG_AGENT_INFO=/run/user/1000/gnupg/S.gpg-agent:0:1
dbus-update-activation-environment: setting SHLVL=1
dbus-update-activation-environment: setting LANGUAGE=en_US:en
dbus-update-activation-environment: setting LOGNAME=farina
dbus-update-activation-environment: setting DBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/1000/bus
dbus-update-activation-environment: setting XDG_RUNTIME_DIR=/run/user/1000
dbus-update-activation-environment: setting XAUTHORITY=/home/farina/.Xauthority
dbus-update-activation-environment: setting XDG_SESSION_PATH=/org/freedesktop/DisplayManager/Session1
dbus-update-activation-environment: setting PATH=/home/farina/bin:/usr/local/bin:/usr/bin:/bin:/usr/local/games:/usr/games
dbus-update-activation-environment: setting GTK_IM_MODULE=xim
dbus-update-activation-environment: setting _=/usr/bin/dbus-update-activation-environment
kcm_input: Using X11 backend
startkde: Starting up...
kdeinit5: preparing to launch '/usr/lib/x86_64-linux-gnu/libexec/kf5/klauncher'
kdeinit5: Launched KLauncher, pid = 1529, result = 0
Connecting to deprecated signal QDBusConnectionInterface::serviceOwnerChanged(QString,QString,QString)
kdeinit5: opened connection to :0
kdeinit5: preparing to launch 'libkdeinit5_kded5'
kdeinit5: Launched KDED, pid = 1538 result = 0
kdeinit5: preparing to launch 'libkdeinit5_kcminit_startup'
kdeinit5: Launched 'kcminit_startup', pid = 1539 result = 0
Initializing "kcm_access" : "kcminit_access"
kdeinit5: Got EXEC_NEW '/usr/bin/kaccess' from launcher.
kdeinit5: preparing to launch '/usr/bin/kaccess'
Initializing "kcm_style" : "kcminit_style"
Xlib XKB extension major= 1 minor= 0
X server XKB extension major= 1 minor= 0
kdeinit5: Got SETENV 'GTK_RC_FILES=/etc/gtk/gtkrc:/home/farina/.gtkrc:/home/farina/.config/gtkrc' from launcher.
kdeinit5: Got SETENV 'GTK2_RC_FILES=/etc/gtk-2.0/gtkrc:/home/farina/.gtkrc-2.0:/home/farina/.config/gtkrc-2.0' from launcher.
kf5.kded: No X-KDE-DBus-ServiceName found in "/usr/lib/x86_64-linux-gnu/qt5/plugins/kf5/kded/khotkeys.so"
kf5.kded: No X-KDE-DBus-ServiceName found in "/usr/lib/x86_64-linux-gnu/qt5/plugins/kf5/kded/colorcorrectlocationupdater.so"
kf5.kded: No X-KDE-DBus-ServiceName found in "/usr/lib/x86_64-linux-gnu/qt5/plugins/kf5/kded/ktimezoned.so"
kf5.kded: No X-KDE-DBus-ServiceName found in "/usr/lib/x86_64-linux-gnu/qt5/plugins/kf5/kded/solidautoeject.so"
kf5.kded: No X-KDE-DBus-ServiceName found in "/usr/lib/x86_64-linux-gnu/qt5/plugins/kf5/kded/bluedevil.so"
kf5.kded: No X-KDE-DBus-ServiceName found in "/usr/lib/x86_64-linux-gnu/qt5/plugins/kf5/kded/desktopnotifier.so"
kf5.kded: No X-KDE-DBus-ServiceName found in "/usr/lib/x86_64-linux-gnu/qt5/plugins/kf5/kded/filenamesearchmodule.so"
kf5.kded: No X-KDE-DBus-ServiceName found in "/usr/lib/x86_64-linux-gnu/qt5/plugins/kf5/kded/kwrited.so"
kf5.kded: No X-KDE-DBus-ServiceName found in "/usr/lib/x86_64-linux-gnu/qt5/plugins/kf5/kded/statusnotifierwatcher.so"
kf5.kded: No X-KDE-DBus-ServiceName found in "/usr/lib/x86_64-linux-gnu/qt5/plugins/kf5/kded/appmenu.so"
kf5.kded: No X-KDE-DBus-ServiceName found in "/usr/lib/x86_64-linux-gnu/qt5/plugins/kf5/kded/networkstatus.so"
kf5.kded: No X-KDE-DBus-ServiceName found in "/usr/lib/x86_64-linux-gnu/qt5/plugins/kf5/kded/recentdocumentsnotifier.so"
kf5.kded: No X-KDE-DBus-ServiceName found in "/usr/lib/x86_64-linux-gnu/qt5/plugins/kf5/kded/device_automounter.so"
kf5.kded: No X-KDE-DBus-ServiceName found in "/usr/lib/x86_64-linux-gnu/qt5/plugins/kf5/kded/freespacenotifier.so"
kf5.kded: No X-KDE-DBus-ServiceName found in "/usr/lib/x86_64-linux-gnu/qt5/plugins/kf5/kded/kscreen.so"
kf5.kded: No X-KDE-DBus-ServiceName found in "/usr/lib/x86_64-linux-gnu/qt5/plugins/kf5/kded/proxyscout.so"
kf5.kded: No X-KDE-DBus-ServiceName found in "/usr/lib/x86_64-linux-gnu/qt5/plugins/kf5/kded/baloosearchmodule.so"
kf5.kded: No X-KDE-DBus-ServiceName found in "/usr/lib/x86_64-linux-gnu/qt5/plugins/kf5/kded/networkmanagement.so"
kf5.kded: No X-KDE-DBus-ServiceName found in "/usr/lib/x86_64-linux-gnu/qt5/plugins/kf5/kded/ksysguard.so"
kf5.kded: No X-KDE-DBus-ServiceName found in "/usr/lib/x86_64-linux-gnu/qt5/plugins/kf5/kded/keyboard.so"
kf5.kded: No X-KDE-DBus-ServiceName found in "/usr/lib/x86_64-linux-gnu/qt5/plugins/kf5/kded/remotenotifier.so"
kf5.kded: No X-KDE-DBus-ServiceName found in "/usr/lib/x86_64-linux-gnu/qt5/plugins/kf5/kded/soliduiserver.so"
kf5.kded: No X-KDE-DBus-ServiceName found in "/usr/lib/x86_64-linux-gnu/qt5/plugins/kf5/kded/networkwatcher.so"
Initializing "kcm_input" : "kcminit_mouse"
kcm_input: Using X11 backend
kdeinit5: PID 1539 terminated.
kdeinit5: Got KWRAPPER '/usr/bin/ksmserver' from wrapper.
kdeinit5: preparing to launch '/usr/bin/ksmserver'
Initializing "kcm_access" : "kcminit_access"
kdeinit5: Got EXEC_NEW '/usr/bin/kaccess' from launcher.
kdeinit5: preparing to launch '/usr/bin/kaccess'
org.kde.kcoreaddons: Expected JSON property "X-KDE-OnlyShowOnQtPlatforms" to be a string list. Treating it as a list with a single entry: "xcb;"
Initializing "kcm_style" : "kcminit_style"
kdeinit5: Got EXEC_NEW '/usr/lib/x86_64-linux-gnu/libexec/kf5/kconf_update' from launcher.
kdeinit5: preparing to launch '/usr/lib/x86_64-linux-gnu/libexec/kf5/kconf_update'
2018-03-03T11:32:22 Checking update-file '/usr/share/kconf_update/akregator.upd' for new updates
kdeinit5: Got SETENV 'GTK_RC_FILES=/etc/gtk/gtkrc:/home/farina/.gtkrc:/home/farina/.config/gtkrc' from launcher.
kdeinit5: Got SETENV 'GTK2_RC_FILES=/etc/gtk-2.0/gtkrc:/home/farina/.gtkrc-2.0:/home/farina/.config/gtkrc-2.0' from launcher.
2018-03-03T11:32:22 Checking update-file '/usr/share/kconf_update/disable_kmix.upd' for new updates
2018-03-03T11:32:22 Checking update-file '/usr/share/kconf_update/fonts_akregator.upd' for new updates
2018-03-03T11:32:22 Checking update-file '/usr/share/kconf_update/fonts_global.upd' for new updates
2018-03-03T11:32:22 Checking update-file '/usr/share/kconf_update/fonts_global_toolbar.upd' for new updates
2018-03-03T11:32:22 Checking update-file '/usr/share/kconf_update/fonts_kate.upd' for new updates
kdeinit5: PID 2975 terminated.
2018-03-03T11:32:22 Checking update-file '/usr/share/kconf_update/gtkbreeze5.5.upd' for new updates
2018-03-03T11:32:22 Checking update-file '/usr/share/kconf_update/kaddressbook.upd' for new updates
2018-03-03T11:32:22 Checking update-file '/usr/share/kconf_update/kcalcrc.upd' for new updates
"Missing \"Version=5\", file '/usr/share/kconf_update/kcalcrc.upd' will be skipped."
2018-03-03T11:32:22 Checking update-file '/usr/share/kconf_update/kde4breeze.upd' for new updates
kdeinit5: Got KWRAPPER '/usr/bin/ksmserver' from wrapper.
kdeinit5: preparing to launch '/usr/bin/ksmserver'
2018-03-03T11:32:22 Checking update-file '/usr/share/kconf_update/kmail.upd' for new updates
2018-03-03T11:32:22 Checking update-file '/usr/share/kconf_update/kmail2.upd' for new updates
Xlib XKB extension major= 1 minor= 0
X server XKB extension major= 1 minor= 0
2018-03-03T11:32:22 Checking update-file '/usr/share/kconf_update/knotes.upd' for new updates
2018-03-03T12:08:29 Checking update-file '/usr/share/kconf_update/akregator.upd' for new updates
At this point Desktop login already took 1 minute (11:32:22 – 11:31:27)
while
Laptop login took 3 seconds (12:08:29 - 12:08:26)

Does it do this EVERY time you start up such as boot up > shutdown > boot up?

How about if you just reboot?

What is the software resources update frequency ?

It happens ALWAYS, no matter if system comes from logout/login, reboot, boot .

I typ update the system every 2 days.

Creating a new user and login, does not help .

Thanks