I found out that disk access was the bottleneck of the optimisations. So I used a RAM disk software to create a disk-drive in RAM. It increased the simulation speed by orders of magnitude.
Anyway, the RAMLink was powered but you could also get a battery backup for it (using a sealed lead-acid battery, like a miniature one used in a car). I could move an operating system called GEOS over to the RAMLink and watch it boot in less than 20 seconds, where it usually took 1.5 minutes to read off disks and eventually load. I could then move programs (word processing, graphics creation, terminal programs - you name it) over to the RAMLink and open and use them in 1-2 seconds max.
This is from 1990 technology, running on computers from the mid-80s. RAM Drives/Disks are awesome.
But in general it was not worth the setup hassle and the possible RAM-starving of other server jobs, stuff was generally not urgent.