Why does my Task Manager show i have 4 open RAM slots? — Acer ...
You don't. Its likely the chipset which is common to other designs supports 4 ram slots. There's only 2 physical ram slots its entirely possible to use the same chipset for 4 sticks.
Should You Use 2 or 4 Sticks of RAM? Here's What You Need to Know
That being said, you need to follow a specific order when you insert the RAM sticks in the slots. ... After removing the modules, carefully take the new memory sticks along the edges, put them on the slots, and gently push them down.
Where Is RAM In Device Manager? (8 Ways To Find)
If I keep the topmost RAM slot empty and I put some of my RAM sticks in the other three slots the iMac will start.