It is possible to increase the cache of the underlying Attaché database (Ctree Ace) which can, in some instances, unlock performance improvements.
The configuration options are in the AttacheServer\ctsrvr.cfg file.
The default is either 100 MB, or 750 MB per line, depending on the age of your ctsrvr.cfg file and whether you initially had Attaché Server 32 bit installed.
This value can be increased to any number of megabytes, assuming that the server has enough total RAM to handle the caching and continue normal processes.
On Windows Server 2012 R2 and later, Terminal Services Fair Share features are enabled by default. This has been known to cause performance issues with Attaché due to the limitations imposed on CPU, disk and network usage.
The three options can be switched off manually in the registry or via the Win32_TerminalServiceSettings class.
Making these changes require a server reboot and should only be made by an IT professional who is qualified to make registry changes.
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Quota System\