Virtual Memory - WTH?

[deanops]

so, i finally got my ram today (2x1gb sticks for $105AU) im pretty happy at that price but please, for your sake, do not use AUstralian Air Express... sh*t service, and they only deliver b/w 8am and 1pm - in other words, when everyone is working/at school.... sheesh


so, looking at my ram usage today, i can see the advantages of 2gb of ram HOWEVER, my VM is still using 19gb Why might this be/

thanks for any help


sorry for digging up an old thread

 

[Phil A.]

so, i finally got my ram today (2x1gb sticks for $105AU) im pretty happy at that price but please, for your sake, do not use AUstralian Air Express... sh*t service, and they only deliver b/w 8am and 1pm - in other words, when everyone is working/at school.... sheesh


so, looking at my ram usage today, i can see the advantages of 2gb of ram HOWEVER, my VM is still using 19gb Why might this be/

thanks for any help


sorry for digging up an old thread

The VM size in OSX is a constant source of confusion: it doesn't mean the same as the page file size in Windows (which is allocated swap space).

VM Size in OSX doesn't mean that that much memory is in use, or that hard disk space has been allocated to support it, it is the total amount of memory that all applications currently running could theoretically ask for.

I've just checked Activity monitor on my MacBook Pro running leopard and it shows a VM size of 60.69GB(!). Fortunately on Leopard, it also shows Swap Used (which, as I said above, is what a large number of people mistakenly think VM Size refers to) and this is a more realistic 795MB.
Hope this helps!

In short, looking VM Size in OSX is not the right way to determine if you're running out of RAM (and is largely a pointless exercise): What you need to look at is Page Ins and Page Outs (and, in Leopard, Swap Used)