initdb and CREATE DATABASE take TOO MUCH time on Win7

Hi all.

My team is developing a product using PostgreSQL as the database. During testing, the QA group found that on some
computers'initdb' and 'CREATE DATABASE' take much more time than that on others. 

For example, on my computer, 'initdb' takes less than 4 seconds on an SSD, 10 seconds on a normal hard disk. 'CREATE
DATABASE'takes 0.8s for the SSD database. While on my colleague's computer with similar hardware configuration,
'initdb'takes almost 1.5 _minutes_, and 'CREATE DATABASE' takes 1min 14sec! After finding that, I was totally shocked. 

Having tried some googling, but didn't find anything useful. Could anyone give me some ideas?

Environment:
- Windows 7 x64
- PostgreSQL 10.1 x86