Fast downloads but slow page loads

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It's getting kind of hard for me to browse the web. Pages take so long to load that it's not a matter of when when I can read them but if. They often time out before they've loaded. I thought I might just have a slow connection but I noticed when I download something it goes reasonably fast. Not super fast but at about the speed I'd expect for my type of connection, ADSL2+.

So, does anyone have an explanation? Does anyone have a solution?

Many (most?) web pages will hit an average of 15 different host names for various pieces of the layout (images, banner ads, tracking cookies...). One of the things that slows this down horribly regardless of your bandwidth (download speed) is DNS, which is a sort of "phone book" that maps human-friendly names to IP addresses (computer-friendly names). If the DNS server assigned to you by your Internet service is overloaded, or is network-wise "far away" (high latency), then each and every different host name (could also be called "site name", though host name is proper) has to be looked up in DNS in order to obtain the numeric digital IP address to connect to. If your DNS is slow to respond then each of these (remember, 5-30 per page!) will incur an additional delay before anything can be loaded from the server on the other end.

For example, and using the 15 host names in the average example page, if this delay is around 1 second then your page (which may not contain but a split second of actual data transfer) would take 15 seconds before even loading anything. Most web browsers will fire these requests simultaneously (shotgun), and most personal routers will remember a reasonable number of recently referenced host-to-IP mappings, so generally if this is your cause, then the previously slow site would pop up nearly immediately upon a reload within a minute or two of the first try.

To solve this, you could override whatever your Internet provider supplies with a public DNS server such as one run by Google (8.8.8.8) or OpenDNS (208.67.222.222) and perhaps get much faster response (lookup) latency. This only redirects your DNS host-to-IP lookups and no other traffic, so your data (once DNS tells your computer where to get it) should be just as fast as a sustained download. Also if you do not have a router in between your DSL modem and your computer, you can add one (even if you only have one computer) and let it do the DNS caching, which usually remembers more hosts than the OS on your computer would do on its own. But, I would bet your ISP has sluggish DNS servers, and if they are too slow your computer will just plain give up on waiting and act as if the site doesn't exist (or, an image on the page won't load, or the CSS styling won't load, leaving a page that looks unlike it should, or missing features or showing broken image icons).

Follow up, just noticed you're down under, you may need to search for some closer public DNS services as the ones I suggested (Google and OpenDNS) are in the US and would be slow for you to use regardless. The point being to find one (or, a pair) that are fast to respond, and use those.