To measure the load time of our website, we need a good website testing tools. My choice is a pingdom website tool i.e (website speed optimization), it will analyze the site and gives a report about the general performance.
You can place the same google adsense code multiple times on a web page. The reason goes for different ad code is size. To place google ads which size is suitable for the page you want to track and position in your page to get maximum clicks.