Available CPU cycles and I/O capacity can impose severe restrictions on performance. Resolving and preventing such issues is necessary to optimize system performance (in addition to configuring the HADB optimally.)
If there are additional CPUs on the host that are not exploited, add new nodes to the same host. Otherwise add new machines and add new nodes on them.
If the machine has enough memory, increase the DataBufferPoolSize, and increase other internal buffers that may be putting warnings into the log files. Otherwise, add new machines and add new nodes on them.
For more information on this subject, consult the Performance and Tuning Guide.