Loading JSON

Just looking from a performance point of view, does anyone know if its better to load JSON code with an AJAX call to a external JSON file compared to just having the code entered directly into C2?

So

System | On start of layout -> AJAX | Request myData.json (tag "myData")

AJAX | On "myData" completed -> myArray | Load from JSON string AJAX.LastData

compared to

System | On start of layout -> myArray | Load from JSON string "{ all my JSON code entered here }"

I'm working on a major project at the minute and will need to create 1000+ JSON files, so performance is key