(Computer spec) How to prevent being slow with tons of image?

I have Mac Pro 2010 which is very old but decent enough to work with Capture One Pro 20 execpt for fine art. 

I have several series and I put all photos in sessions per series. I shoot images and then store them together. One of my series' session already have over 2000 of images shot by A7R2. Obviosuly, Capture One Pro is little bit slower and buggy as I scroll up and down from the browser. Loading the session is also slow. 

So just wondering, do you think adding more RAM can solve this problem or HDD is just not able to keep up with the performance?