Pages being stolen by another process or the file system cache.
Monitor the RSS memory of the FairCom DB process (ps v PID) to see if it drops at the times of poor performance.
Set the FairCom DB SQL executable and/or the system for large page support.
On 64-bit Windows systems, by default, the Windows file system cache can grow without limit, causing Windows to "steal" memory pages from user processes such as FairCom DB. The reported symptom is that FairCom DB sometimes becomes unexpectedly slow, in particular for accessing memory files and cached data.
Microsoft provides a utility that limits the file system cache size. The link below can be used to download this utility: