Why do thumbnails take so long to load in windows explorer on windows 10 with 64GB RAM and an SSD with the photos and operating system on it

I bought a new computer because I was sure the problem was lack of RAM. Now I guess it isn't.

When I open a folder in windows explorer, I want to see all my photos (big PNG) with extra large icons. I want bigger, but the computer gods have determined that nobody has eyesight as poor as mine, so nobody could possibly want thumbnails any larger. That I get past with magnification, so I'm not asking about that unless somebody has a miracle option to make bigger thumbnails. 

The problem is my thumbnails only load when they come onto the screen, and it takes about 5 seconds to load a row or two of thumbnails. This seems ridiculous, since I can open the folder, then leave and come back, and it has waited for me so I can watch it load photo by photo as I scroll down. 

I searched the internet, and got an article starting off with something like group policy editing, and it didn't seem to exist as instructed, so I gave up. 

I did download a program called AC-Dsee, and it can open full screen photos faster than Microsoft can load a thumbnail. It's now faster to find a photo by opening the first one in AC-Dsee and just scrolling through the hundreds of photos in the folder, since as I said, Microsoft takes most of a second to load a single tiny thumbnail, but AC-Dsee can load the whole picture without a noticeable delay. The problem is, I want to view thumbnails.

Can I make it preload the thumbnails and save them? I wouldn't mind if I could open the folder, go get a cup of coffee, and have thumbnails visible when I get back. It won't. It will load the ones that are visible, then make me wait as I scroll line by line down the folder. Ridiculous. 

What am I doing wrong? I can't believe the operating system is not designed to show me my files in real time.