According to a report published by CPU World, a pair of unreleased AMD Athlon X4 processors appeared in a supported CPU list on Gigabyte's website (since removed) long enough to give away some information about these new FM2+ models.
Image credit: CPU World
The CPUs in question are the Athlon X4 835 and Athlon X4 845, 65W quad-core parts that are both based on AMD's Excavator core, according to CPU World. The part numbers are AD835XACI43KA and AD845XACI43KA, which the CPU World report interprets:
"The 'I43' letters and digits in the part number signify Socket FM2+, 4 CPU cores, and 1 MB L2 cache per module, or 2MB in total. The last two letters 'KA' confirm that the CPUs are based on Carrizo design."
The report further states that the Athlon X4 835 will operate at 3.1 GHz, with 3.5 GHz for the X4 845. No Turbo Core frequency information is known for these parts.