Quick update. I've been looking into this further and have now found that xorg appears to be the CPU hog.
I've got the following errors in the Xorg.0.log but still not finding much to go on.
(WW) The directory "/usr/share/fonts/X11/cyrillic" does not exist.
(WW) The directory "/usr/share/fonts/X11/100dpi/" does not exist.
(WW) The directory "/usr/share/fonts/X11/75dpi/" does not exist.
(WW) The directory "/usr/share/fonts/X11/100dpi" does not exist.
(WW) The directory "/usr/share/fonts/X11/75dpi" does not exist.
(WW) Open ACPI failed (/var/run/acpid.socket) (No such file or directory)
(WW) Falling back to old probe method for vesa
(WW) Falling back to old probe method for fbdev
I'm wondering if the tweaks to grub to startx could be related. I'm running an Intel HD graphics card
For info I added the following to grub and then did a rebuild.
"quiet splash i915.modeset=1 vga=791"


