I don't think so. Am3's support the phenom ii cpu's which are k10 based. The fx series on am3+ is when amd started using bulldozer which is the first in the amd lineup to support sse 4.1 and 4.2. There might be a bios update for a particular am3 motherboard which allows using an fx cpu but it's not always a guaranteed solution. Some people have updated their bios claiming to support fx chips and it either has extremely limited fx support or still none at all.