🚀 go-pugleaf

> I have an C++ Builder 5 application using Indy 5.  

There is no Indy version 5.  IIRC, CB5 included Indy 8.  I would use Indy 9 (at a minimum), or Indy 10 (the current code base for development).  

> It listens on specific TCP ports for incoming traffic and full 
> sockets are created for a communications session with an 
> external device.  This software has been in use for several 
> years and has worked fine with Windows 98, NT and 2000.  
> However, there is a connection issue when running under 
> XP (Pro, non-SP2 and with SP2).  The response time of the 
> listener is significantly slower and that causes problems with 
> some of the devices that communicate with the application PC.  
> Are there any known issues with XP that would cause this behavior?

In my experience, Win XP is slower than Win2K.  Period.  My newest PC came with XP Pro installed.  After spending a week trying to tweak and tune, I reformatted the hard drive and installed Win 2K.

There could be some Indy-specific issue that needs to be resolved for WinXP, but I am not aware of anything specific at this point.