Buy low-profile RAM for big coolers.

Yes, if your cooler actually overhangs the RAM slots. Standard-height RAM (like most RGB sticks) will hit the bottom of a big air cooler and either not fit or force you to raise the fan, which hurts cooling.

Low-profile RAM is usually a few millimeters shorter—just enough to clear the cooler. The extra cost is small ($10–$20), and the alternative is a return headache or a worse-running PC.

Check your cooler’s clearance spec first. If it says something like “max RAM height 32mm” and your RAM is 45mm, you need low-profile. If there’s no overhang, save the money.

Future you doesn’t want to be installing RAM with a half-inch clearance gap.