I was trying to add some RSS feeds on my Wordpress site. The plug-in is called WP RSS Multi-importer, and it is based on SimplePie.
I've tested my feed url in the SimplePie demo website and it works. Very fast.
However, my GET request to the page that contains the feed takes about 30 seconds! and even fails sometimes. It doesn't happen on the other pages. If you don't mind, I attached the website page where I'm testing it out here.
EDIT: I forgot to say that the website is currently hosted in my computer running in WAMP.