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.
I have experienced similar issues with the HyperX 120 on Gigabyte X58A-UD7 rev.2 currently running beta bios version FD13 , was worse with FD12 . Running the drive on Marvell port .
Just for interest sake - I got E5620 working on Gigabyte X58A-UD3R rev.2.0 with beta bios from Stasio - FF2 . Beta bioses here .
I think that if the E5620 works , the L5640 should too .
I don't know if it made a difference - but I flashed bios w i7 950 , went into the bios and manually set...