RACF® can save ACEEs (accessor environment elements) using VLF (virtual lookaside facility) and retrieve them for later use. If you have multiple requests to RACF to build a user security environment (ACEE), you can benefit. You might see improvements in areas such as logon, batch job submissions, MVS/APPC, and CICS® reconnect. The amount of improvement is related to how often RACF finds the necessary data in VLF.