A memory problem would be server-specific and not linked to a router replacement. Plus, I believe they said things would be monitored for 12 - 24 hours to be sure the network problem is completely solved, even though it seems that it is.
Are you on poprock? If so, I believe there was another thread that said there was going to be a memory swap.
Everything seems fine to me, and there don't seem to be many complaints here after the upgrade, so I'm not sure why you think everyone is in the same boat.
If you're not on poprock, you should probably send support a ticket if you haven't already. Or maybe check the load average threads to see if anyone else reported a problem on whichever server you're on.
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