Well, I wonder if you are fixating on the wrong problem. You have a fairly large database which does need sufficient RAM, so having increased RAM is ok. But still, your processor is a Gen 6 i7, with benchmark results not up to my Gen 8 i5. Roon definitely does at times CPU-stressing processing, and this will make power usage indication go up. Power usage is relative to your platform.
What you should talk about is the user experience when using the system from a Remote. In your original post you talked about ‘slowdown’; what exactly slows down? Do these slowdowns still occur after the RAM update? Do the slowdowns eventually go away and the system feels normal again?
I also notice slowdowns from time to time. This is, the user interface on my Mac Remote suddenly feels sluggish at scrolling or at performing searches, page loads are slowed down, saving a new album into the database is slower than normal. As I do regularly monitor my Roon server, I can say with total confidence that these slowdowns always are related to Roon processing metadata updates or related processes which keep the server occupied. As soon as these processes terminate, the user experience is back to normal. Of course these processes with your large database size (which doubles mine in track count) will last noticeably longer.
What I would try to do is to correlate the user interface responsiveness, the experience when using the system on your Remotes, with what the Roon server is doing at that moment… On Linux there is the very handy tool tail, which allows to follow a log file as it is written to. This in Windows isn’t directly available, but there seem to be ways to achieve the same. I have not been using Windows for the last 15 years or so, so I can’t try this here nor can I guarantee that it really works. But have a look here:
If you can make this work, you can ‘tail’ the Roonserver log file on your Windows server, while using the system normally from any of your Remotes. If you notice a slowdown, have a look at the lines being added to the Roonserver log, as this will give you clues about what the Core is doing.
One last point. You posted in a forum category which is not usually being followed by Roon support staff. If you wish, I can recategorize your post into the Support category, so you will receive help by Roon staff.