Importing Text Files very slow in V12 but not in V11



I've been importing several text files of a thousand refs each into a V12 database.
As it was taking up to 30 mins for each text file (on my ref man Web Publisher server computer which has V12 intalled) I decided to do some tests by importing the same text file into a new database each time on different computers:


All versions are network versions.
V12 - On my ref man Web Publisher server it took 25 mins to import
V12 - In the University computer cluster the same text file took 15 mins to import
V11 - On my regular work computer, in V11, it took 2 mins to import.  I then had to save the database onto a memory stick and transfer it to the ref man Web Publisher server to upgrade it to V12, this took about 10 seconds to upgrade to V12


By the way, I am unble to install both V11 and V12 on my regular work computer hence my having to faff around copying databases to memory stick to transfer them to a computer that has V12 installed in order to upgrade them.
Can you anybody please?