Spaghetti on toast, lol, at least it ain’t beans on toast, Blazing Saddles camp fire symphony 
I do hope you ordered DDR2 synch Dram non-ecc memory (2x2GB modules), as the Dimm capacities of each slot is 2GB or up 4 modules at 2GB.
I would suggest you practise doing the tweaks with your current desktop when your extra ram arrives, delete the Mate desktop using Gparted through the LiveCD and then install Linuxmint Xfce or Lubuntu, with your usual “Erase and Install Linuxmint” to sda.
Tweaks and tips
Reduce Swappiness and cache pressure (both share same file)
cat /proc/sys/vm/swappiness normally set at ‘60’, ideal for a server, not desktop
sudo nano /etc/sysctl.conf
scroll to bottom of file and add the following
# Reduce the swap tendency
vm.swappiness=20
Then
cat /proc/sys/vm/vfs_cache_pressure normally set at 100
sudo nano /etc/sysctl.conf
scroll to bottom of file and add the following
# Reduce Cache Pressure
vm.vfs_cache_pressure=75
Important to run this command:
sudo update-grub
sudo shutdown -r now
Clear thumbnail cache
rm -v -f ~/.cache/thumbnails/*/*.png ~/.thumbnails/*/*.png
rm -v -f ~/.cache/thumbnails/*/*/*.png ~/.thumbnails/*/*/*.png
Then
sudo apt install dconf-editor
click on org > gnome > desktop > thumbnail-cache
click on maximum-age and set it to 30 days
click once on maximum-size and set it to 50Mb
Clear Recent Files
cat /dev/null > .local/share/recently-used.xbel
Check file and filesystem
sudo apt autoclean && sudo apt autoremove
sudo dpkg --configure -a
sudo apt clean
Broken Packages
sudo dpkg -l | grep ^..r
sudo apt install -f
Check boot up time
systemd-analyze time
systemd-analyze blame
systemd-analyze critical-chain
Disable network service
sudo systemctl disable NetworkManager-wait-online.service (if it retards boot up time)
Good luck with the quacks
