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.
Given the architecture differences (Atom has 2 integer execution units vs 3 for the Isaiah), the results aren't too surprising. CrystalMark is multi-threaded, so that kind of helps the in-order execution, hyper-threaded Atom compete vs the out of order execution Isaiah core.
The Atom 1.6GHz is a Silverthorne model with a 2W TDP (an Atom 1.66GHz would be a Diamondville model with a 4W TDP). The Isaiah 1.6GHz is a 20W TDP model.
It looks like you will really have to decide on a trade-off. Small devices like MIDs, PDAs or phones won't even use the higher clocked Isaiah models due to the relatively high power usage. Even the slowest LV Isaiah versions use over 2x more power than the fastest mobile Atom models. SFF desktop boards and very small laptops can use either one and power draw will be a secondary or primary concern after performance, respectively.