I got a new Nokia Lumia 810 almost a month ago, and I seem to be experiencing the same sort of freezes as the 820 and 920 owners. The first freeze occurred almost immediately after setup, the second the next day, and since then the freezes vary between once a week randomly to several times within a half hour pretty much if I want it to, meaning I can virtually prompt freezes by browsing the web and/or pulling up the keyboard. This morning, for instance, I got it to freeze about once every two to three minutes at will (note, however, I can only seem to do this in the morning, for whatever reason).
I've updated my 810 to the latest firmware, uninstalled everything that can be uninstalled, removed all but my Microsoft Account, disabled Bluetooth, Wi-Fi, NFC, and location services, performed hard resets, used no memory cards, disabled "Find My Phone", etcetera, etcetera, to no real avail. Returning or exchanging my 810 is not an option because I didn't buy it from an official channel, and from what I gathered from the seller this particular unit is a new exchange (it came factory-sealed), so there's already precedent for that not guaranteeing a fix.
I'm not really mad about this, nor does this cause me to want to switch to another platform or anything like that (the grass is always greener, and my phone last round was an Android phone, so I know exactly how "green" it is). There is no "or else" for me so long as my 810 is otherwise functional (and it is), and I don't want to have to leave the WP platform again, so I sincerely hope there is a fix or at least an official acknowledgment coming soon.
Just to update this thread, about a month ago I sent my 810 to Nokia to repair. Nokia apparently reflashed the firmware, and after determining all was good, sent it back to me in about a week. Great turnaround, by the way.
Unfortunately, about a day after I got my phone back, it started freezing again. On the up side, it froze much less frequently than before (nowhere near once every few minutes), but after another freeze in the morning resulting in the alarm clock not going off, I figured I had enough dealing with this excellent but wholly unreliable phone. I was preparing to put it on eBay "as-is" and eating the loss before I stumbled on a forum thread... somewhere... suggesting that at least some of the freezing might be due to the Nokia charger. With a few other users in that thread reporting similar findings, and having nothing to lose myself, I plugged my phone into my computer to charge that night just to see if there was any truth to their findings.
Now, I'm not claiming any conclusions here, but after two weeks of charging the 810 via anything other than the Nokia charger it came with, i.e. a Samsung charger, a car charger, my computer, etc., I have so far experienced zero freezes. I don't know how. I don't know why. This could all be a huge coincidence, and my phone could freeze within the next few minutes just to punk me. It doesn't even make sense to me, since the freezing occurred both on and off the Nokia charger. But for now... no freezes!
Okay, scratch my last post. My 810 started freezing again about a day or so later.
One more RMA... one more... and if that doesn't resolve this issue, then I'm done with this phone. I'm sorry.