How long does a GSO Boost take to update positions across multiple Categories or Collections?

Once a GSO Boost is applied and saved, the updates run at a speed of around 50 Product Listing Pages in 10 minutes. If a GSO is applied to around 50 Product Listing Pages, the updates will be sent to the Platform within the next 10 minutes. 

The Product Positions will be updated in the front-end post that, based on your Platform's Cache preferences.