Again, we are not discussing 'normal' here and 8GB/stick RAM ... well it's finicky ... all RAM throws errors. Yes, even ECC has errors, but the difference is ECC has the ability to correct its errors whereas non-ECC does not correct the errors. Therefore, the more volume of 'work' (processing) the higher the likelihood of an error, now some errors aren't any huge deal but some can halt or corrupt the entire process which is the reason I went to the trouble of mentioning it in the first place. 'IF' this is final production work then IMO Xeon + ECC and I prefer RDIMM.
As far as putting together (2) two identical kits of 4x8GB now and later the bigger risk is often IC's are different (updates, production runs, etc) but the P/N remains the same or the mixing issue as I already explained or worst a discontinued set.
Lets play the guessing game, say you purchase a 4x8GB set now and later you get the verbatim set 4x8GB, then there's no guarantee that they'll work as Rated nor in XMP -- so what do you do?! Well for starters try to increase some voltages and if needed set the (CL-RCD-RP-RAS-CR) manually but leaving the remaining CAS Timings as Auto which are are a tad slower i.e. safer <or> lower the Frequency DDR3-1600 -> DDR3-1333 <or> increase the CAS Timings (9-9-9-24 -> 10-10-10-30) ; example voltages:
DRAM -> (1.50v) -> 1.55v ; +0.05v
VCCSA -> (1.10v) -> 1.15v or (1.20v) -> 1.20v ; don't exceed 1.20v but you might increase the DRAM Phase control.
PLL -> (1.80v) -> 1.85v ; +0.05v
Then Memtest for a minimum of 4-full passes; I'd do 8-full passes or at least 24 hours. If you get >1 error then stop and reevaluate.
Testing, I treat a 'PC' differently than a 'Workstation' and essentially double the testing periods. PC: Memtest 4-passes, and AIDA64 (all stress options) 24 hours; Workstation: Memtest 8-passes (generally 24 hours straight), and AIDA64 (all stress options) 48 hours.
There's no such a thing as a simple answer, and if I'm around then PM (Private Message) me if you have any troubles and/or start a new Thread and let me in on it.
IMO 8GB/stick non-ECC isn't yet ready for 'prime time' and the IC's still need to be improved. That's the sole reason I'm running 32GB (DDR3L) instead of 64GB on my home PC. I use it to test and code SQL @ home. BTW - 'test' not final production which is entirely done on Xeon's and RDIMM ECC RAM.