Just a quick follow up on the  "garbage" I mentioned above. Two folders I clean fairly regularly are:
 
C:\Users\[main user name]\AppData\Local\Temp  and
C:\Windows\Temp
 
Both of these tend to house files which get used in one session and never get cleaned accept by the user, so they can get fairly big over time.
 
Having just done my first Win10 update (from 1709 -> 1803), Windows leaves its old version on the drive (30+ GB). I just imaged that drive with Macrium Reflect, and although it took twice as long, the image is the same size, so apparently Reflect doesn't copy that with default settings. To me this is not paramount, since I am on 1803 without issues, but to actually save those would require tweaking Reflect to image them.
 
To recover that space, you need to run "Disk Cleanup" on C: and select "Clean up system files" at the bottom. This exposed 1.54GB of "Windows Update Cleanup" and 29.7GB of "Previous Windows Installation(s)". Jim mentioned this above, but I didn't realize the size of these until I got to see it for myself (that is a hefty percentage for a small SSD!).

Good info guys, appreciate all the details. I also noticed that 30GB Windows/Sys files, but just left them alone. Will take a look at cleaning up the older version to free up some more space.
 
I forgot that I had a folder on my desktop I use for collaborations containing all WAV files which had about 30GB....deleted all of that and moved a few libraries (10GB) to my samples drive which cleaned up my C: drive. So all in all, my C: drive is looking much, much better, but will look into that 30GB Windows System files.
 
Cheers!!
Mesh  

The 30GB "Windows.old" from your last Windows upgrade is placed there in case you want to "roll back" to the old version.  If you are satisfied with the upgrade, you can use disk cleanup to remove it.
 
Windows should automatically remove it at some point.
 
https://www.howtogeek.com...-how-do-you-delete-it/

To remove the "Windows.old" you just need to run Disk Cleanup (including System Files).
You should have a backup of the OS (if not, I'd make one ASAP).

Jim Roseberry
To remove the "Windows.old" you just need to run Disk Cleanup (including System Files).
You should have a backup of the OS (if not, I'd make one ASAP).

Done and done!! :))

Wow, I just came across this thread.  Great stuff!
 
There must have been something in the air about a month ago with PrimoCache.  I've been experimenting with it as an assist to my video editing ambitions. As observed earlier in the thread, I also haven't found much in audio (beyond sample loading) that makes life better using these new hyper-fast devices or caching schemes. 
 
I have a 3-part article about the PrimoCache journey on my website.  [www.tedlandstudio.com/articles]. It's called Homemade Hybrid Disk Drives.
 
Since I've written it, there have been more changes to the disk farm because of some nasty surprises.  (None of the surprises were related to PrimoCache; just that HGST 3TB drives are happy with my 4-bay USB towers and HGST 2TB drives are not happy. Go figure.)
 
Anyway, I'm now going to work/play with WinDirStat and TreeSize.  Thanks to all!