Hi,
While setting up QuickSight account, you get 1GB free tier and then for each Author added to your QuickSight account an additional 10GB of SPICE capacity will be added. So your 11GB in SPICE capacity = 1GB Free tier + 10 GB for an author in your account. This 11 GB will be shared across all datasets created in your account. If the size of any single dataset or total size of all datasets in your account exceeds this limit you are required to buy more SPICE capacity.
In enterprise edition, a single SPICE dataset can have up to 500 million rows (or 500GB) of data, provided you have enough SPICE capacity purchased in your account.
Regards