I have two copies of SimPE on my computer:

0.66.2.38582 (alpha)
0.73.44.37511

The new version takes between 45 and 60 seconds to open. While the old one opens in about 15 seconds. The new one also uses more memory with both a small and a big package open. On the splash screen it says that it's loading Objects, Scenegraph Wrapper Factory, and more objects from every expansion pack. I seem to have no need for these if I use the PJSE editor, but I don't see a way to disable them to make the program load as fast. I often need to open two or three copies of SimPE to compare files, and this takes a long time. Some text listings are more complete in the new version, but it is not a big deal.

If I interrupt the loading while opening a neighborhood, I usually can't use SimPE and must close and open it again. But I must use the new version to open an Apartments neighborhood. There seems to be no need to reference any objects while editing a neighborhood either.

Why is there so much difference between the programs?

Memory use with Objects open and 42k items sorted alphabetically: https://i.imgur.com/BOMA0DX.png

Memory use with a small package open: https://i.imgur.com/Dhx64HO.png

Do you have different file tables selected with the versions? If you run SimPE with the -localmode switch then it will load quickly, without the file table, so that you can open a package without waiting.

It's the first time I hear about localmode. It could be useful in some circumstances, but not every day. Too much stuff is missing from PJSE editor: bhav, constant labels, attributes, relationship names.

0.66 seems to postpone loading of other components until later. Sometimes there is pause when opening a new type of dialog for the first time.

It can access almost all expansion files because I expanded expansions.xreg. They are all checkmarked in Preferences -> FileTable.