There is no indication of the 4100 being unlockable, so don't buy one expecting to get a free FX8150. For a 120 dollar budget the Core i3 2100 walks all over Bullsnoozer.
Only the most deluded AMD fanboys buy that CPU, which is why it has good reviews on Newegg. All impartial reviews point to Bulldozer being a Faildozer. If you want to write it off as "media bias" be my guest.
Main system: Core i7 3770k @ 4.5ghz, Gigabyte GA-Z77X-UD5H-WB, 32gb Corsair DDR3 1600 RAM, EVGA NVIDIA Geforce GTX 970x2,
Tablet: Surface 3
Phone: Nexus 6