Some users have recently had their accounts hijacked. It seems that the now defunct EVGA forums might have compromised your password there and seems many are using the same PW here. We would suggest you UPDATE YOUR PASSWORD and TURN ON 2FA for your account here to further secure it. None of the compromised accounts had 2FA turned on.
Once you have enabled 2FA, your account will be updated soon to show a badge, letting other members know that you use 2FA to protect your account. This should be beneficial for everyone that uses FSFT.
Could be any number of things :
Undervoltage, chip instability period (over the maximum output of chip), ram timing problem, ram voltage, ram frequencies....
Thats why it's best, when oc'ing, to find each components level of stability, so that when it does crash during the oc'ing of your system, you know exactly why.
For example.. We isolate an OC problem and it happens to be voltage. As long as it's "stable" it doesn't matter what voltage it's at? Assuming temps are within range.