When running SCCM 2012 Prerequisite checker, it will show a warning related to SQL Server memory usage. Basically what it means is, SQL Server is configured for unlimited memory usage. You should configure SQL Server memory to have a maximum limit.
To address the issue, we need to limit the SQL memory usage.
Launch SQL Server Management Studio and connect to the SQL Server
Right click on the Server name and Open the Properties
On the Properties Window, Select memory node.
The default setting for minimum server memory is 0, and the default setting for maximum server memory is 2147483647 megabytes (MB). The minimum amount of memory you can specify for maximum server memory is 16 MB.
Change the maximum server memory 2147483647 megabytes (MB) to 1024.
Click OK then re-run the SCCM 2012 Prerequisite checker. Now the warning should disappear.