Here is Mike’s explanation of Qspice64/Qspice80.exe. Qspice80.exe utilizes 80-bit math in critical sections. In the forum, you can find several cases where Qspice80 can produce accurate results while Qspice64 cannot, as these cases require higher-precision math. Personally, I changed my default to use Qspice80.exe. However, you can see from the post below that Mike recommends using Qspice64 as higher precision is rarely needed.
Running qspice from command line? - QSPICE - Qorvo Tech Forum
It appears that your laptop limits its CPU clock in battery power mode. Great to know what slow down the simulation!