While it used to be a common practice to address performance issues with front-end server load-balancing to distribute the load (website traffic) between several front-end servers installed on separate machines, the switch to 64-bit JVM and the advancement of the architecture, in the direction of smaller self-contained units (instances), make this practice - even for larger installations - rather unnecessary.
It is more beneficial to focus on the performance of the machine that is hosting the database server and the database in general. For large testing environments, Micro Focus recommends increasing the amount of independent Silk Central instances, where each instance has a dedicated database.