crwFor TF2 only should I go with 4 core CPU (e.g. Athlon 860k) or a 2 core with better single core performance (e.g. g3258)?
Buying a dual-core for gaming isn't a good idea since like 2010 and might cause wierd problems in some games like BF3
tbh the way things are going i'd recommend an AMD 6 or 8 core CPU just so that you dont have to upgrade for some time
but yeah TF2 can run on a dual core processor perfectly fine