Undo Command

[#1]

Does  disabling the table undo command in JMP 12 result in more useable RAM?

[#2]

Here is the information provided under the Help==>Help Contents    when you search on Undo

Disable Undo

Removes all actions from the undo history and does not record future actions. Undos are disabled only while the data table is open; the setting is not saved with the data table. This option prevents memory overruns when you delete rows and perform other tasks in the data table.

So the answer is "Yes"