Physical Address Extension (PAE) is a feature to allow (32-bit) x86 processors to access a physical address space larger than 4 gigabytes. This includes RAM {Random Access Memory} and memory mapped devices.

Sometimes referred to as PAE-Highmem.

If the computer has more than 4GB RAM use the PAE version

If the compute has 4GB or less RAM memory, use the standard non-PAE version. The CPU may not support the PAE kernel.

Some versions of Puppy have a PAE version available, including Puppy53 Puppy 5.3 Slacko

PAE is not only more physical address space but also important for the "no execute" feature which disables execution of code that is marked as non-executable.

Therefore, the PAE kernel should be used on any systems that support it, regardless of the amount of main memory.

Barry's Blog post - See comment by scsijon