DC Power Supply Output Caps: Electrical Advantage to using many smaller capacitors instead of few large?
Smaller size capacitors have lower ESL. Paralleling many of them lowers ESR and ESL further. This can lower noise on the output of a switching regulator, but very low ESR can also create a high Q resonance when interacting with other capacitors on the power bus. When comparing 10X 10uF to 1X 100uF you have to consider if they are the same type of capacitor or not. For instance 10uF might be ceramic and 100uF might be tantalum or electrolytic. Ceramic capacitors loose capacity proportional to DC bias voltage, this is worse for smaller size packages. 10X 10uF ceramic may only give you 50uF. Ceramic capacitors are also limited in capacitance so if you need 100uF or more, chances are you need to parallel them.