Serverの場合、Serverサービスのプロパティオプションで変更可能です。Workstationの場合は手動でレジストリを変更します。
0:Minimize memory used.
1:Balance (cache and working sets have equal priority).
2:Maximize throughput for file sharing (the cache has a higher priority).
3:Maximize throughput for network applications (the working sets have higher priority).