Help - REST client performance

I have an application that uses the curl command (actually a php module that calls the libcurl library) to retrieve data from a NetSuite RESTlet.

This morning the performance of that application went down hill in a big way.

However, when I use the Postman REST client, I still get good performance.  Even on the first call, it returns in 3 seconds or less.  Subsequent calls return in less than a second.  The same curl command with the same REST URL with the same parameters executed on multiple servers on different networks in different cities all perform the same - 18 to 20 seconds.   I've tried Postman on two different systems on different networks and get excellent performance on both.  I even tried curl under cygwin on the same Windows box where Postman runs in 3 seconds.  I get