Has anyone noticed that a PC that is communicating to the inverters shuts the daily timer down on the inverter related to increased traffic on the computer.

GT-View doesn't do anything in relation to processor loads, what you are seeing is either the GT-View is failing to communicate with the inverter because the RS232 traffic is not being responded to in a low latency manor or it can be your graphic card is not keeping up when the processor load increases.

GT-View 1.8, when fast pc mode is unchecked, polls at 400ms, which even on 500 mhz PC's seems to work OK, I updated this to 400ms for a user that monitors 7 inverters with a single 500mhz PC and does so with GT-View 1.8, if you haven't updated yet, this might improve your situation

What is your PC type specs? do you have fastpc mode unchecked? and what does task manager show for processor utilization when the problem occurs?