Max server memory left at the default

SQL Server loves memory. If you do not cap it, it will take what it can — and the operating system still needs room to breathe.

A very common health-check finding: max server memory still at the default (effectively uncapped).

Symptoms you might already feel

• OS free memory chronically low
• Other services on the box (SSIS, antivirus, RDP, monitoring) starve
• Occasional sluggishness that is not “a bad query” alone
• Failovers or restarts that behave differently under load

What we set and why

On dedicated SQL boxes, max server memory is sized so that:

• The OS retains a healthy reserve
• Other installed components get a budget
• Multiple instances do not cannibalise each other

There is no single magic number for every server — it depends on total RAM, role, and neighbours. Guessing is better than default; measuring is better than guessing.

Related checks in the same review

• Locked pages / privilege configuration (where appropriate)
• min server memory misuse
• Memory clerks and grants for runaway queries
• Whether the problem is memory starvation or bad plans that thrash the cache

Bottom line

Leaving max server memory untouched is not “letting SQL optimise itself.” It is skipping a basic hosting decision. It is also one of the first configuration items we fix after a free health check.