Cpu mining is dead for zcash, save your money and get the cheapest cpu available as makes no difference to GPU mining speeds
G1840 or G3258 should be fine, i think someone i know just built it with G3258, it worked fine for 7 GPUs, i imagine G1840 will work fine also
I have the same problem. Running exactly same settings as v.3a which gives me about 42 sols.
But any version after that just ends with a crash. “not authorised”
Is it limited to some certain pools? I was trying suprnova