looking at buying a new ryzen 3900x Processor, but want to see if the current AIO i have will fit it.
If the manufacturer's product page states it is compatible with Socket AM4, then yes, if not, then no.
Swiftech has lousy website support. But at Newegg is mentions it uses Apogee XL2 Series Waterblock. Found that waterblock at swiftech and it mentions it can be used on AMD but you need to order the Option AMD4 Installation Kit: Apogee XL2 - Rouchon Industries Inc., dba Swiftech - PC Liquid Cooling Systems CPU Cooler VGA Water ...
This is from Newegg where the H240 X2 is being sold and its features: