okok.. u are not particularly good with tier list..
tier list is a list created by tomshardware for people like us to get the best psu..
tier 1 -very good psu
tier 2 -good psu
tier 3- average psu(u should avoid these from here)..
b1 is a tier 3 psu which is not good for u pc and might damage your components when it fails..
b2 is a tier 2 psu which is good with low failure rate..