Slow to begin the download

When we first click the download button, it takes quite a while to start the download and bring up the window to choose a folder to save to on local machine.

The file is large, 39MB. Once the download starts, it goes quickly. Is there a setting or something I can adjust so the “save to” dialog box comes up more quickly and users don’t just give up?

http://macdougalstreetwest.com/electronic-press-kit/

(Use the Download EPK button.)

Thanks for any suggestions.