The changes that were made to the Dev API Server a few weeks back (detailed here: https://app.roll20.net/forum/permalink/386277/) are now on the Main API servers as well.
In addition to that, we upgraded the hardware of the Main API Servers to keep up with demand, doubling the amount of memory and processing power available to the cluster (we were reaching around 85% capacity during peak times before).
I should have the new Sheet Worker API stuff on Dev for testing later this week/early next.
Thanks!