If the formulae for the computed columns are deterministic (in SQL Server's opinion), then you can persist the values, and even index them if you want to.
Here's a sample of what that looks like:
CREATE TABLE dbo.DropMe (
ID INT IDENTITY PRIMARY KEY,
CompCol AS ID+1 PERSISTED);
If the column is persisted, the value in it will be calculated when the row is inserted/updated. If it isn't persisted, it will be calculated at runtime.
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