Networking :: Internet Very Slow Unless Reboot Router Every Few Days WRT160N

A few weeks ago, I noticed that my Internet connection had slowed down to a crawl. I waited a few days hoping it would go away on its own, but it didn't get better. So I asked this question about how to make it faster.

The problem went away after I updated to the latest firmware, so I didn't follow up too carefully. But every few days since then, my Internet has slowed down again. Unlike before, all I have to do to fix it is open the router administration page and press the "Reboot" button. Nothing else seems to work, though I'm sure there are options I haven't tried.

If it makes a difference, my girlfriend and I both transfer large amounts of data fairly routinely for school (videoconferencing, downloading entire recorded lectures).

The router is a Cisco/Linksys WRT160N v3 that's about a year old. Most of the time, it deals with just two standard Windows 7 laptops.

What could be causing these slowdowns, and how can I get rid of them?

I installed dd-wrt on my router, and I seem to be getting higher and more consistent speeds. Perhaps more importantly, my memory use is fairly constant.