chf8845The 8642 is the one that's having the issues. Our guide is Trio. It's strange because we've had Cox since November but this issue just started about 2 weeks ago. I don't think it has anything to do with the specific channels because it'll even happen if I just press the guide or dvr menu buttons, there will be a pause before anything happens. It seems completely random just once out of every 10 or so times I push a button on the remote, but if you're a channel surfer like me it'll really bug you.
The 8642 comes with 384M RAM standard with 512M optional. I have no idea how the RAM is utilized. Possible that some of your RAM has failed since you say you tried a re-boot with no success. I'd try leaving it unplugged for 5-10 minutes, and then let it boot up. If this fails, you might have to try a new DVR. Hope your HDD isn't too full.
Trio had an upgrade toward the end of last year. A few features were added, and a few bugs were fixed. I noticed the DVR acted more sluggish after the upgrade. That's what worries me with next month's push of Trio 2. And it is why I eagerly wait for the G8 DVR (Cisco 98xx) and its 1GB+ RAM (up to 3GB is optional.) We'll see.