At what volume of data does a JSON data structure become too slow?

Question

I'm using MIT's Simile to display thumbnails and links with faceted filtering. I works great, but large data sets (greater than 500 elements) start to slow significantly. My user base will tolerate seconds, but not 10's of seconds, and certainly not minutes while the page renders.

Is it the volume of data in the JSON structure?

Is it Simile's method of parsing?

Answer 1

Too slow compared to what? Its probably faster than XML and easier to implement compared to your own custom binary format.