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.
There's no native gpu client for linux at this time.
A phenom x4 should be well worth running the linux SMP client on.
If you want to really dive in head first, there are ways to run the windows gpu client under linux, and you can certainly learn a bit doing it.
Google around, there's a guide on FoldingForum.