Page loading time loading two partial views every 30 seconds

I have two partial views which I am loading every few seconds usign ajax and set interval. TesterPartialView is taking mostly lesser time(ms) though not always and ViewAttributes1 makes calls to database and loads data from database every 30 seconds and it is taking a lot of time to load most of the time though not consistent. I am only testing my app in my local machine and I see loading time in ms and seconds. Couple of questions

1. Why isn't the loading time consistent? sometimes one view is faster and sometimes not and the same for the other view too. It is highlighted in the image
2. Is this a normal loading time? 500ms or .50 seconds for loading a view on your local machine, local web server and local database?If not what can I do to improve performance.
3. My requirement is DB gets updated by another program and hence I did the set interval in jquery and calling controller method every 30 seconds to get the updated data and then load the view.

I am using asp.net MVC 4 with sql server 2012 and VS 2013. Please advise.