I would have to say that 98 is faster (generally). Espcially when it comes to simulators. Reason being that 98 allows direct access to the hardware... of course it is far less stable than 2000 and XP.

Windows XP is a major upgrade from Windows 98 in the home market, providing improved stability, increased performance and a series of extras designed to help home and small-business users more easily ...

Microsoft officially launched Windows 2000 for businesses and organizations on February 17, 2000. 24 years after its launch, it has become somewhat forgotten due to the launch of Windows XP in 2001.