Darryl notices his internet speed slows down to 0.5 Mbps upload and download until he resets his modem and router. There are a few things he could do.
- Call Comcast and have them replace the modem
If he's renting his modem from Comcast, he should call them and tell them that this is consistently happening. They should replace it.
- Buy his own modem
If he keeps having problems with Comcast's modems, he could get his own.
- Make sure he's using DOCSYS 3.0
Not only does he need to have a modem capable of using DOCSYS 3.0, but he needs to make sure they're sending him that from Comcast.
- Check his DNS performance
There are a number of DNS testers, and there is a free one called "DNS Benchmark" from grc.com
- Check the Netalyzer
http://netalyzr.icsi.berkeley.edu/ - this will test many different things on his network to see where the problems are.