<edited a bit ... a lot...> > From: [EMAIL PROTECTED]
> At 09:41 AM +1000 05/04/2004, David Elmo wrote: >> I hear it said to turn off VM if one has say >> 500 MB of Ram or more... Why? > > IMO, there are only three reasons to turn off VM: > > 1) You need the extra performance during audio/video capture or > poorly written game. > > 2) You're a photoshop geek and need that xtra 3% performance and have > already used all your HD space to build Photoshop-scratch volumes. > > 3) You have a boatload of RAM and very little free HD space, so you > don't have room for the swapping/paging file. > > Turning off VM (in OS 8.6 and later) disables part of the shared > library manager. This decreases system performance by about 1%. > >> Is it that when VM is on, the whole memory allocation is randomly or >> widely used (thus immediately bringing on the slowness of seek and >> read of HDs into the equation)? If real memory is always used first >> and VM used as "overflow" >> then it seems to be a plus to have it on. > > Even when VM is off, paging translation still occurs in the > processor. So there is no performance diff there. > > The system doesn't start paging things out until most of your RAM is > used. So when you have lots of RAM, that's not usually an issue. > > One diff you will see... With VM off, the entire application is > loaded when launched. That makes for longer launch delays but less > read i/o while the app is running. With VM on, parts of the app may > not be read until they're actually needed. This makes for faster > launches, saves memory, but then incurs read i/o at a later time. > > - Dan. Your last point, Dan, is a good enough reason for me to put in a bit of extra memory I have (to go to over 800) and turn off VM and see if I am happy. I am in a mood lately to need a theoretical reason for doing most things. OK, I said most things... David Elmo -- PCI-PowerMacs is sponsored by <http://lowendmac.com/> and... Small Dog Electronics http://www.smalldog.com | Refurbished Drives | -- Sonnet & PowerLogix Upgrades - start at $169 | & CDRWs on Sale! | Support Low End Mac <http://lowendmac.com/lists/support.html> PCI-PowerMacs list info: <http://lowendmac.com/lists/pci-powermacs.shtml> --> AOL users, remove "mailto:"; Send list messages to: <mailto:[EMAIL PROTECTED]> To unsubscribe, email: <mailto:[EMAIL PROTECTED]> For digest mode, email: <mailto:[EMAIL PROTECTED]> Subscription questions: <mailto:[EMAIL PROTECTED]> Archive:<http://www.mail-archive.com/pci-powermacs%40mail.maclaunch.com/> Using a Mac? Free email & more at Applelinks! http://www.applelinks.com
