BE6 UPgrade Prob

My Problem: After upgrading from a Cel 500 to a PIII 850 system intermittently gives a Fatal exception OE has occurred at xxxxxxxx in VCACHE VXD(01) + xxxxxxxx. The current app will terminate. The system will need hard reboot. Everything appears towork fine under light load. This problem occurs during burn in testing and heavy file I/O applications like video rendering. Memory is PC100, the CPU has 100MHz bus, MB has the latest TH bios upgrade. The last two Bios revs have supported the 850(100).