This isn't a problem. The article says that this is only if you're looking to trade-off performance for less noise:
> In other words, we would only recommend upgrading to the NF-A12x25 G2 if you seek to lower noise levels as much as possible and if you are willing to sacrifice the maximum performance headroom in worst-case scenarios that the G1 HS-PWM fan provides.
> In other words, we would only recommend upgrading to the NF-A12x25 G2 if you seek to lower noise levels as much as possible and if you are willing to sacrifice the maximum performance headroom in worst-case scenarios that the G1 HS-PWM fan provides.