Hyper transport sync flood error occurred on last boot

my config is
msi 880gm-e35
amd phenom 555be
corsair vengeance 4gb
nvidia xfx gts 250 core edition
seagate 500gb sata
coolermaster extreme power 600

i have this hyper transport sync flood error occurred on last boot sometimes when i'm surfing the net or doing nothin at all on the desktop..the system just goes blank and restarts with a black screen with the message hyper 'transport sync flood error occurred on last boot,press f1 to reboot or del to enter setup'.i didnt overclock my system.wat seems to be the problem?