SQL server timeout after downgrade

After a downgrade from SQL 2008 R2 Enterprise to SQL 2008 R2 Standard. SQL Server after some time starts lagging and CPU use is around 95%-100% and I can't log in in "MS SQL server management studio", another application gets time outs from SQL Server.

The log files don't have any error, but all files are filled with this text:

Log file:

https://drive.google.com/file/d/0B8niPQ9GLmG-ZHFuR3hqQUphMUU

The log seems to display an output of the DBCC MEMORYSTATUS, which is what happens when the engine runs out of memory. Did you configure the maximum amount of memory SQL Server can use ? To find out, you can run the following query :

SELECT  *
FROM    sys.configurations
WHERE   name LIKE '%mem%'

For the row for which the column named "name" is valued to "max server memory (MB)", you should see a value different greater than zero.

If it is set to zero, you can easily configure it with the following code, assuming that you server has a couple GB or RAM and is dedicated to SQL Server :

EXEC sp_configure 'show advanced options', 1
GO
RECONFIGURE
GO

EXEC sp_configure 'max server memory (MB)', [your_server_RAM_amount_in_MB_minus_4GB]
GO
RECONFIGURE
GO

EXEC sp_configure 'show advanced options', 0
GO
RECONFIGURE
GO

This takes effect immediately, without the need to restart the SQL Server instance.

If it is not this, did you update all the statistics of all databases on this instance ?

StackExchange Database Administrators Q#124300, answer score: 2