The performance of a development (DEV) environment is related to a few factors:
1. Number of logged-in users simultaneously viewing reports, uploading data, adjusting models, etc.
2. Number of open projects.
3. Complexity of open projects.
re #1: Establishing a cadence is handy, e.g. set up a schedule for certain DEV users to make changes only during certain times.
re #2: Resetting an instance normally closes all of its projects, except for ones that have been set to automatically reopen upon environment reset. Minimizing the number of open projects (seen in the Open Project menu - distinguish between Open Projects and Other Projects) boosts the amount of environment memory available.
re #3: Large data sets, large model object row counts, complex allocation strategies or data table column formulas...in general, the longer your project takes to precalculate on STG or PRD, the longer you might expect to wait when making adjustments on DEV.