When a OPC client is connecting to Vista the updates of values in Vista get really slow.
The OPC client is asking for values from a Lon network
TAC Vista 5.1.7
Vista OPC server
IFix OPC client in this case but could be any
The problem here is that the OPC clients asks for more values per second from the Lon network then the Vista server can deliver.
The Visa server can read around 40 values per second using a Loytec network interface in a classic Lon network.
Make sure the OPC client doesn't read more then maximum 30-40 values per second from Vista.