For a list with 1700 items, you will face a delay on load. The only option that comes to mind is to somehow create a cascading filter. For example, let's say the items are divided into Categories. The user would first select a category in the IP form. Based on the selected Category, then the second dropdown will show the list items that match that category. So instead of 1700 items in one dropdown you would be retrieving perhaps 250 items, producing a performance improvement.
Good luck!