25 percent of physical memory
1 percent to maximum amount of physical memory
When using NCA on a system with more than 512 Mbytes of memory. If a system has a lot of physical memory that is not being used, increase this parameter. Then, NCA will efficiently use this memory to cache new objects. As a result, system performance will increase.
This parameter should be increased in conjunction with nca_vpmax, unless you have a system with more physical memory than virtual memory (a 32-bit kernel that has greater than 4 Gbytes memory). Use pagesize(1) to determine your system's page size.