How much memory does Excel allocate for custom number formatting

[bearcub]

I've been working a lot recently with custom number formats and if using custom number formatting takes up my memory than cell fill.

This came to my attention when I was ";;;" to hide the cell contents from view as opposing to using a white fill or a white font. I am curious to find out if Excel uses more resources to custom number formatting than it does for conditional formatting, cell fill, borders or font color.

Does anyone know of any good articles I could read on the subject or happen to know off hand which one takes up more Excel resources?

Also, I understand the starting in Excel 2016, there doesn't seem to be the 64,000 custom format limitation as in earlier versions. Is this true or is there still a limit before Excel "crashes" or you get the message that Excel is out of memory, etc.

Thank you for your help,

Michael