Admin getting logged out frequently (2.65)

I just upgraded to 2.65 and I am finding that when I am working in the admin pages I am being logged out CONSTANTLY. I can work for maybe a minute or so, then things seem to stop responding, and then sometimes I find myself back at the login page, and sometimes things just seem to stop responding all together and I have to close my browser and log in again.

Anyone have any ideas about what the problem might be?

See this topic: https://www.nopcommerce.com/boards/t/11727/admin-logs-out-too-frequently.aspx.

I assume you're referring to the machine encryption key suggestions? I guess I can try that, but my site is running on a single server not a web farm, so I'm not sure if that's going to make a difference. Thanks for the pointer.