On the Reprap Motherboard v1.1 (3rd gen):

The schematic diagram, silkscreen values, and photo illustration show that capacitors C1 and C2 should be 22pF. However, the wiki page text and the Bill of Materials state that they should be 15pF. Could the wiki be clarified on this?

Although someone should probably fix the ambiguity, either value will almost certainly be fine. If this is halting your build, go for whichever you have on hand.