Ansys will use what it needs to use in terms say of RAM (so for a small model with one beam element it would not need to use say 128 GB of RAM).
If you want to look at improving speed and solution time, look at HPC and DMP options (distributed solutions) – see the help manual under the:
Parallel Processing Guide
(Search for that in help)
There should be also many other resources on this in help and on the internet.
All the best