Don't bother reusing DDR4 RAM coolers on DDR5.

Probably not compatible, and definitely not worth the hassle.

DDR5 sticks look similar, but the guts are different. The power management IC (PMIC) and voltage regulators moved onto the stick itself, which changes the PCB layout and component heights. Clip-on coolers designed for DDR4 often won’t clear those parts—or worse, they’ll press down on them and cause shorts or physical damage.

Even if it physically fits, DDR5 modules have different thermal characteristics. They run hotter in some spots and cooler in others. A DDR4 cooler wasn’t designed for that heat distribution, so you might not get any benefit. Plus, most DDR5 sticks already come with decent heatsinks from the factory.

Save the money for something that actually fits.