The Network tab in Chrome DevTools has an option to faux throttle your network, so you can experience what your users might experience visiting your website on 3G, 2G and GPRS connections. Besides the obvious, it's also useful for visualising how fonts load.
Here’s how to do it in Chrome v.46:
Open DevTools (cmd + alt + i)
Click the ‘Network’ tab
Select which type of connection you want to imitate
Reload the page to see assets downloading at that connection speed
If the standard options aren't to your liking, you can even make a custom Network Throttling Profile by clicking the option at the very top of the dropdown menu.