Capacity Management - Office Web Application Service limits

Limit	Maximum value	Limit type	Notes
Cache size	100 GB	Threshold	Space available to render documents, created as part of a content database. By default, the cache available to render documents is 100 GB. We do not recommend that you increase the available cache.
Renders	One per document per second per CPU core per application server (maximum eight cores)	Boundary	This is the measured average number of renders that can be performed of "typical" documents on the application server over a period of time.