SCRAM-SHA-1, by design, consumes a great deal of CPU resources while performing authentication. This can be a problem while populating connection pools, where many clients are authenticating at once. Fortunately, most of the expensive computations of SCRAM can be reused across multiple authentication requests. RFC5802 makes provisions for this:
Note that a client implementation MAY cache ClientKey&ServerKey (or just SaltedPassword) for later reauthentication to the same service, as it is likely that the server is going to advertise the same salt value upon reauthentication. This might be useful for mobile clients where CPU usage is a concern.