Great question @Das_Praxisteam!
Piggybacking off @Shannon_McNeil’s recommendation, I also recommend grouping Tasks for each Patient in small bucket Projects. I could even go a step further & suggest a Project for each patient, that way, if they have more than one visit or the need for a space to add additional information, then the Project serves as an easy reference point for this.
What you should avoid, on the other hand, is if you have all 8,000 patients serve as individual Tasks in one burgeoning Project. Choosing this method would slow down your experience considerably. The use of Advanced Search (if you’re on a premium plan) as well as custom fields (as Shannon mentioned) will help you locate your patients pretty quick.
An important thing to keep in mind when considering effects on performance, whenever you operate within a Project with too many Tasks, the process of downloading from the server upcoming Tasks (when scrolling down to view more) is typically where the slowdown & drag in performance is experienced most. Any way you are able to avoid this, will be a performance win for you and your Team
Hope this helps clarify some things, though definitely happy to dig deeper on this if anything is unclear here