Why wouldn't it be? That "Haswell ready" thing is just marketing. It's the same as "skype ready" headphones, so if it isn't marked that they are skype ready, does that mean that they won't work with it? No, its just placed to attract people that don't have a lot of knowledge about electronics. Most of the good products don't have that "Hasswell/Vishera ready" crap because they don't need marketing tricks to be sold.
But also be aware that AMD CPUs have a considerably bigger power consumption, so can you tell us what model of your PSU and the rest of the build?