Well Dust clean out done a month ago, but took time this morning to check all connections, all tight as can be, so that's not it, reloaded system, Restarted Comcast Gateway (DPC 3941T), while that was restarting reinstalled Avast with Offline installer, restarted PC, redid the exclusions for Firestorm viewer, restarted again.
Results: After Second Restart, reopened usual programs, one Microsoft Edge viewer, Windows 10 Mail app, Skype Preview, and of course Firestorm Viewer X64, Memory usage was down, stayed around 55 to 63 Percent entire evening, also adjusted Firestorm video memory usage from 2048mb to 1024mb for textures, thinking it could've been using all of the video memory, plus using system memory/swap file when it used all of the video memory, with texture memory lowered, it seemed to have resulted in working better thus far.
Previous Av was just Windows Defender built into Windows 10 Pro 64bit 1607
(Ran for about a day when I resetup system from clean install back in September)
Drivers up to date
Antivirus and Malwarebytes scan done as well, 0 infections found
Think I covered about everything possible, so hopefully the problem does not return, and system keeps performing perfectly