Hello,
Thank you for posting in Q&A forum.
Although you have taken some optimization steps and there are no obvious network lag or database query performance issues, there may still be some factors that cause VB6 applications to run slowly on Windows Server 2019.
The following are some factors that may cause performance differences:
Operating System Differences: There are significant differences in kernel and system architecture between Windows Server 2019 and Windows Server 2003, which may result in different performance of applications on different operating systems.
Compatibility issue: Although you have set user compatibility to Windows XP and excluded VB6 applications from antivirus applications, there may still be other compatibility issues, especially for older versions of applications.
Resource allocation: Although there is no significant lag between your network and database servers, there may still be other resource allocation issues. Ensure that the server has sufficient memory, CPU, and disk resources to meet the requirements of the application.
Hardware differences: Windows Server 2019 may run in different hardware environments, which may be different from the hardware environment where Windows Server 2003 is located. The difference in hardware performance may affect the running speed of applications.
Code optimization: Consider conducting performance analysis and optimization on VB6 applications to identify bottlenecks that may cause performance degradation, such as long running queries, memory leaks, or inefficient algorithms.
In summary, in addition to the measures already taken, a more in-depth investigation and analysis of the application is needed to identify the root causes of potential performance differences and take corresponding measures to improve performance.
Hope this answer can help you well.
Best regards,
Jill Zhou