Fill6251

Thanks for the advice much appreciated. I am looking into if there are any new video drivers needed to be installed now. 

A lot of those things you had to do in when SSDs were finally becoming mainstream and the OS wouldn't know what to do with it. Windows 8 and beyond however do know when an SSD is installed and it will configure itself appropriately.
 
Also that first point. If you weren't enabling AHCI in 2012, you must be using an old OS.
 
And removing the page file is a bad idea.

If you were already using up ~300gb of space in your hard drive's properties then no.  But by system image I assume you mean a backup you created.  Sometimes the software you would use to create an image would bloat it in size depending on the method it uses - including the blank allocated space in the partition.  So shrinking the windows partition may help reduce the size if you weren't using that much space.
 
I would personally back up my data and start over, but you did mention you were trying to avoid this.  It would be best to back up your crucial data somewhere else if possible.