The values are in Bytes when you see it from VisualVM
"Size: 208,928,768 B Max: 268,435,456 B Used:B" as we have maxpermsize=256MB.
(Max) 268,435,456 Bytes = 262144 KB = 256 MB
(Used) 151,287,656 Bytes = 147741 KB = 144 MB
What do you think How much memory should it be using? If you are expecting less memory consumption then can you please let us know why? And Which kind of application are you running ?
Sorry for late revert. You are absolutely correct, i was misunderstood somewhere. Thanks