Limited virtual space available for Symantec Protection Engine (symcscan) service, which impacts scanning performance.
On 32-bit editions of Windows, applications have 4 GB of virtual address space available. The virtual address space is divided so that 2 GB is available to the application and the remainder 2 GB is available only to the system. The 4-gigabyte tuning (4 GT or 4 GT RAM tuning) feature, increases the virtual address space that is available to the application up to 3 GB, and reduces the amount available to the system to 1 GB and 2 GB.
To resolve this issue, enable LARGEADDRESSAWARE for 32-bit applications on 64-bit Windows system, by performing the following steps:
bcdedit /set IncreaseUserVa 3072
For more information on 4-Gigabyte Tuning: BCDEdit and Boot.ini, go to https://msdn.microsoft.com/en-us/library/windows/desktop/bb613473(v=vs.85).aspx