MemoryUsage = 1 allocates a standard amount of memory for NTFS file operations, this is the default behavior.
Setting MemoryUsage = 2 allocates extra memory for NTFS file operations which causes less file operations need occur as more data is held in memory and results in better file system performance and lower system latency. It also means there is less RAM available for other system tasks, but for common gaming and production computer builds the extra RAM requirement is fairly negligible.
To see what MemoryUsage is set to run cmd as Administrator and enter:
fsutil behavior query memoryusage
To modify MemoryUsage enter:
fsutil behavior set memoryusage 1
This setting is in the Registry Editor under the Key:
Computer\HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\FileSystem
The REG_DWORD Value is named NtfsMemoryUsage and its Data contains the same corresponding number as FSUtil Behavior MemoryUsage.