You can also get much more technical with determining where to set ‘max server memory’ by working out the specific memory requirements for the OS, other applications, the SQL Server thread stack, and other multipage allocators. (Note: This counter should remain above the 150-300MB at a bare minimum, Windows signals the LowMemoryResourceNotification at 96MB so you want a buffer, but I typically like it to be above 1GB on larger servers with 256GB or higher RAM) This has typically worked out well for servers that are dedicated to SQL Server. Then monitor the Memory\Available MBytes performance counter in Windows to determine if you can increase the memory available to SQL Server above the starting value.
Traditionally questions about how much memory SQL Server needs were aimed at how to appropriately set the ‘max server memory’ sp_configure option in SQL Server, and in my book the recommendation that I make is to reserve 1 GB of RAM for the OS, 1 GB for each 4 GB of RAM installed from 4–16 GB, and then 1 GB for every 8 GB RAM installed above 16 GB RAM.
