It’s my understanding that dishwashers generally do not have a heating element, so the hot water is coming directly from your water heater. I believe you should run the sink water till it gets hot before starting the dishwasher, and not run cold water until the dishwasher stops filling. They generally share the same line. If the dishwasher had a dedicated water line I imagine it wouldn’t make a difference, but most inexpensive dishwasher models and homes share with the sink.