Running Slow

WordPress is running EXTREMELY slow and will not run the more elaborate parts of any theme that I install (sliders, etc.). If I try to update the page it will spin and then ask me to kill the pages because they are unresponsive. I have tried 3 different themes and contacted GoDaddy to see if it was something on their end which they assured me it wasn’t. Overall the entire site is running poorly and doesn’t show all elements most of the time. HELP!