Can't tell by label alone, really, that I am aware of. Need to physically inspect the stick, Samsung and very obvious since they have "SAMSUNG" written right on the PCB. Hynix, on the other hand, tends to use just a number, and few ICs can do these speeds, so that kinda points us in the right direction already.
Nice review as always, sorry to go OT a little but I have often heard that anything over 1600mhz with fairly tight timings doesn't show much if any real world impact, that you would notice anyway.
Personally I have found that higher RAM speed definitely does improve Windows boot time (when using an HDD anyway as it probably wouldn't be noticeable with an SSD), I just want to know from your experience is this something you have seen or am I just experiencing a placebo effect?
Meh, depends on the system. Windows booting is very much affected by drivers that are loaded as well, so it could simply be a driver change affecting your boot times. I do see gains with higher speed memory, but it's not in every application, that's for sure. There are measurable differences in the benchmarks I use, too. Multi_GPU systems can also see some worthwhile benefits, but usually multi-GPU users buy high-end ram too, anyway.