Hi,
Its very difficult to confirm from the data that you have provided as to what is the cause of OnCommand Console Slowness. But you can definitely increase the jetty server mem using the below options
[root@vmlnx ~]# dfm options list | grep -i webUIM
webUIMaxHeapSizeMB 1024
webUIMaxPermGenSizeMB 512
webUIMinHeapSizeMB 256
webUIMinPermGenSizeMB 128
[root@vmlnx ~]#
Regards
adai