To improve ISPF performance consider using these methods, which are described in detail here:

• Use virtual I/O (VIO) (see Use virtual I/O).
• Remove or tailor edit functions (see Remove or tailor Edit functions).
• Remove action bars from ISPF panels (see Remove action bars from ISPF panels).
• Remove scrollable areas from ISPF panels (see Remove scrollable areas from ISPF panels).
• Preprocess ISPF panels (see Preprocess all ISPF panels).
• Add load modules to LPALST (see Add load modules to the pageable link-pack area (LPA)).
• Allocate execution data sets (see Allocate execution data sets).
• Disable generic searches (see Disable generic high-level qualifiers).
• Preallocate ISPF temporary data sets to VIO (see Preallocate ISPF temporary data sets to VIO).

Here are some other suggestions, which require no further description:

• Use a workstation editor to make many changes to a file
• Use Browse instead of View for large files
• Use a workstation compiler (whether in SCLM or not) for unit test compiles (such as C++SET/2 or COBOL Productivity Suite)
• Use an action bar to call other functions from Edit or Browse if you intend to return to the Edit or Browse session
• Use the IBM® REXX compiler to compile ISPF dialogs written in REXX.