For many years, sisNET users have been working with large numbers of small-sized reference files. Using small reference files was needed for good performance of MicroStation V8i and older generations, which were 32- bit applications. sisNET CE is a 64-bit application and therefore able to handle much larger DGN files. However, users have reported slower performance of attaching and detaching reference files, especially when using large numbers of them. 

Since CE Update 6, version 10.17.06.26, sisNET contains an important performance improvement for repeated attaching and detaching large numbers of reference files. The improvement depends on several factors, such as the number of reference files, the hardware (physical, virtual, with or without GPU, etc.), the number of times the append and detach process is repeated, etc. This makes it hard to make an accurate prediction of performance improvements, but internal and external tests have shown clear and consistent improvements. 

There are a number of further options to improve the performance of sisNET pool- and reference files:

1. Detach the reference files before you switch in sisNET to another commodity, e.g., when you switch from water to wastewater or from electricity to gas. This can strongly reduce the number of reference files attached to your sisNET session.
2. Take a good look at the zoom-dependencies in your sisNET configuration. Check that only those objects are displayed which are needed at the active scale. The more data you have configured for display, the more reference files will be attached, and the more elements will be scanned for display.
3. As sisNET CE is able to handle much larger DGN files than sisNET V8i, Bentley has developed a tool to merge the existing pool files into smaller numbers. Some users work with thousands of files that each contain just a few hundred Kilobytes of data. It is possible to substantially reduce such numbers of pool files. Testing has shown that performance improvements are achievable for sisNET configurations with more than 300 DGN files. If you have more than 300 DGN pool files in your sisNET configuration, let us know, and we will be pleased to make a service offering to implement this option at your system.