UIWebView first request too slow

The main reason is because, when you invoke the first time URL request, the server on the receiving end tries to display the information as per the requested device browser, ( like mobile, desktop). This is where you see a bit of delay.

• The server take some time to resolve the request origin browse type & respond according to the browser type. This value is internally send from the browser. There is a difference in mobile safari & desktop safari.
• The Server upon receiving the request, responds you back with the device type compatible page, ( mostly all domain servers are implementing this internally, the responsive pages).
• If you want a "no delay situation", try calling the exact mobile version of the portal in concern.
• The sub-sequent requests are treated from a known type browser, hence reducing the delay in response.

Hope this solves the doubt.

The answer of your first question is following:
When you're loading request for the first time, the webview downloads and caches all the files like css, images, etc... After, when you click on a url that brings you to another page of the same website, it's basically loads it from the cache instead of downloading again, and it saves a lot of time.