Perfectforms is a web based tool. This means that the more data you have in your form, the more time it may take to process, similar to any web page that has lots of images, text; it will take longer to load. If you are trying to populate a dropdown with thousands of records, this may create a drain on your resources, not to mention, you wll be requiring your users to scroll through thousands of records.
If you have large amounts of data and you want to populate a dropdown from a database lookup, you may want to allow the user to enter some kind of "filter" information so that you can narrow down your database query and return relevent information into the dropdown.
