Accidently I destroyed one of my 2 sticks of 4GB Corsair vengeance ram 1600MHz (9-9-24) but now I want a new stick of 4gb and ofcourse i want dual channel so I need an identical stick. Now my real question is the ram with this number (8GB) CMZ8GX3M2A1600C9 the same as (4GB) CMZ4GX3M1A1600C9
It's from the same idea 1 Kit vs 2 sticks -- the failure rate of 1 Kit is much lower than the 'mix' even if by all means identical -- if the IC's are different the failure rate is much higher.
Setting the RAM manually (Frequency, CAS Timings, DRAM Voltage, etc) is the best option -- it takes out the risks of an 'Overclock Failure - Press F1 error'. *IF* the OP chooses not to contact Corsair for a replacement.