Overclocking will understandably be very much dependent upon luck of the draw with your individual kit. As such, we don’t assign too much weight to the overclocking results that we see with a sample size of one. There’s no harm in a quick tinker though.
Running at 1.35V for the default XMP configuration, we weren’t comfortable pushing voltage higher when aiming to overclock the kit. We also wanted to keep the stock timings as they’re a clear strength of the kit.
We managed to hit 6200MHz memory speed by simply adjusting the setting in our ASUS motherboard UEFI. 6400MHz would boot but was not stable.
So, a quick-and-easy speed boost up to 6.2GHz whilst maintaining the stock voltage and timings is a perfectly fine increase.