Hey
I gave my brother my 4770 and he put it in his PC, and after 2 hours his PC would lock up and blue screen they he would have to reboot (this is at stock speed) and when he tried launching some games it would say something about an access violation and a quick google said something about memory
his specs are
Gigabyte GA-945GCM-S2L
Intel Pentium D
2 GB RAM
EZCool PSU 550W
I gave my brother my 4770 and he put it in his PC, and after 2 hours his PC would lock up and blue screen they he would have to reboot (this is at stock speed) and when he tried launching some games it would say something about an access violation and a quick google said something about memory

his specs are
Gigabyte GA-945GCM-S2L
Intel Pentium D
2 GB RAM
EZCool PSU 550W