The location of temp files is a VFP and not a FoxWeb issue.  This setting can be found in the registry under:
Software\Microsoft\VisualFoxPro\[Version]\Options\TMPFILES and is specific to the user running FoxWeb.  If you are running FoxWeb as a desktop application then you can log in with the account you normally use and look in the registry under HKEY_CURRENT_USER (or use the VFP Options dialog box).  If on the other hand you are running as a service you will want to find out which account the service is using (the default is SYSTEM) and change it's settings.

The SYSTEM account does not have a subtree in the registry under HKEY_USERS and will usually use the System32 directory as its default temporary location.  For this reason you may want to set the service to run as a specific user, and then log in as this user and change the setting under HKEY_CURRENT_USER.  Note that HKEY_CURRENT_USER is just a pointer to one of the keys under HKEY_USERS, but since it is not easy to determine which key corresponds to which user, it is easier to log in as the desired user and find the value in HKEY_CURRENT_USER.

FoxWeb has another setting, called TempDir, but this location is not used by the VFP engine, but rather by certain FoxWeb components for internal purposes.  You will probably not see much performance improvement by pointing this setting to a RamDisk.

FoxWeb Support Team
support@foxweb.com