I think I DID FIX IT!Update: 2 days after doing this fix, and my internet is running perfect with 210 torrents seeding during the entire time.
I disabled Advanced DNS Service. However, I read that there can be problems if the router is unable to get the DNS or is offline, so I manually added in my ISP's DNS servers.
To do all this, go to your Router's Page, click Status, then Device Info. Note down the DNS servers for your WAN, then go to Setup > Manual Internet Connection Setup. Uncheck Enable Advanced DNS Service, then put in the Primary DNS Address and Secondary DNS Address that you noted on the Status page.
I guess this option normally has the router process all the DNS requests, in case the DNS server doesn't work or something. I really don't know. But I was overloading it with possibly hundreds of requests, or ballooning it's cache.
If I still have problems, I'll update. But right now browsing the world wide web is insanely fast. Pages load almost instantly!
Edit: Currently I also disabled the following "features", which fixed all my router's issues:
- DNS Relay
- QOS (Quality of Service) / Traffic Shaping
- Advanced DNS Service
- SPI
Edit 2: I set my router's DNS addresses to 0.0.0.0 also. No need to manually put in the modem's address.