Wide ranging in SQL from invalid write location, lost read or write, early access to a page that is not yet fully in memory, I/O list damage such as AVs, incorrect timing reports, and many others. You may not even see the situation until days later.
The fix for this will be issued through Windows Update and through SQL Server 2008 R2 Service Pack 2 (not yet released). In the meantime, disable Lock Pages in Memory to avoid these potential problems, if you are using SQL Server 2008 R2 or SQL Server 2012 *unless* you are already running on Windows 8.
In the SQL Server 2012 RTM release, there seems to have been some debug code left in that is filling the Agent log with useless status messages and this can cause performance issues when you are trying to read the log
