EDIT
I just edit this post to add an extra step that needs to be done in case someone just stops reading here and not the whole thread.
This is from a post further down in the thread here
So this is what needed to be done in may case:
edit /etc/mkinitcpio.conf and add microcode to HOOKS line:
HOOKS=(systemd autodetect microcode modconf kms keyboard keymap consolefont block filesystems fsck)
edit preset files for my kernels in /etc/mkinitcpio.d and comment out (or delete) the following line:
ALL_microcode=(/boot/*-ucode.img)
regenerate initramfs:
sudo mkinitcpio -P
Compare the line that begins with HOOKS in following two files:
/etc/mkinitcpio.conf
/etc/mkinitcpio.conf.pacnew
For my part, I just needed to add microcode in the HOOKS line of my mkinitcpio.conf
as is shown below:
HOOKS=(systemd autodetect microcode modconf keyboard keymap consolefont block filesystems resume fsck)
and then rebuild the initramfs:
sudo mkinitcpio -P
for the microcode to be build into the initramfs.
Edit: correcting typo