Hello,
Fixes in Maintenance Release 10 of Symantec AntiVirus 10.1 seems to be addressing this issue.
RTVSCAN uses 100% of CPU for 5-60 minutes
Fix ID: 1879071
Symptom: Rtvscan.exe may consume 100% of available CPU for a period of 5-60 minutes. The issue is intermittent.
Solution: Rtvscan.exe was modified to prevent a case where the IDB processing logic could get into a loop, consuming all CPU.
Blue screen: PAGE_FAULT_IN_NONPAGED_AREA (50) referencing Savrt
Fix ID: 1898155
Symptom: Computer crashes (blue screen) with bug check 50 (PAGE_FAULT_IN_NONPAGED_AREA) when the File System AutoProtect "SmartScan" feature is enabled.
Solution: The Real-time Protection (File System AutoProtect) driver was modified to properly clean up an internal cache when an application terminates, leaving handles open.
I would suggest you to Migrate.