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Lion and Macs with 4GBs of RAM (or even 8GBs)

There is a consistent theme in various Apple Support Communities, here, and in other hardware and software communities


People with Macs which have 4GBs of RAM are asking, "Why is my Mac so slow under Lion, when it worked fine with Snow Leopard?"


I have suggestions for you if you are considering upgrading to Lion, no matter how much RAM you have, but especially if you have 4GBs or less. Lion uses more RAM, and this may hurt your performance after the move to Lion. You need to plan for this


  1. Check Activity Monitor for Page Outs after you have been using your Mac normally for some hours. If Page Outs are zero or very close to zero, then you'll probably be happy with Lion
  2. If Page Outs are not zero, identify your most commonly used apps which are significant consumers of RAM, and change them so that they run in 32 bit mode, not 64 bits, then reboot
  3. Again, check Activity Monitor for Page Outs after you have been using your Mac normally for some hours. If Page Outs are zero or very close to zero, then you'll probably be happy with Lion
  4. If you are still getting Page Outs, then try running fewer apps concurrently, but only if you can live with this compromise
  5. If you still haven't reduced Page Outs to almost zero, then either stay with Snow Leopard, or upgrade your RAM


FAQ


How do I change an app to 32 bit mode?

  1. Go to your Applications folder, find the app, select it and press Command-i
  2. A window will open titled "applicationname Info" and about half way down you should see "Open in 32-bit mode" with a checkbox beside it. Check it.
  3. If it doesn't say that, then look in this window for "Kind". If it says "Application (PowerPC)", then you have another issue to resolve before upgrading to Lion, because this app will not work under Lion.


How much RAM is enough? And how much time should I spend agonizing over how much to get?

  1. RAM is cheap, so if you don't want to spend a lot of time in decision-making, just add at least 4GBs if it will fit, or 8GBs if you plan to keep the Mac for a while, or bite the bullet and just max it out, unless that would be just too expensive.
  2. If the budget is tight, or the Mac is an older one with limits on RAM, consider 2 GBs an absolute minimum upgrade


Why should I change the apps to 32 bit mode? Why can't Apple "fix this problem" for me?

64 bit mode was introduced to allow apps to exploit large memories. Your Mac is not a large memory Mac. This is not a problem to be fixed by Apple. Use the app in 32 bit mode on a small memory Mac.


But Apple says that Lion needs only 2GBs to work! What's going on here?

It is true that Lion will work in 2GBs. It is not necessarily true that the experience will be enjoyable, unless you run apps which have low RAM demand and run few of them. For example, if you just wanted to run TextEdit alone on a 2GB Mac, you'd probably get great performance under Lion. It's marketing-speak. If you ask me, I'd say that 8GBs is the smallest realistic RAM size for Lion if you prefer a hassle-free experience, and if you can get more, do it.


Why is Lion using up more RAM, this sounds like it is less efficient than Snow Leopard, isn't it?

New releases of operating systems always use more RAM. Why? To save I/Os, to save you time, and to fit new function into your system. Because RAM is cheap and getting cheaper all the time, OS designers are always looking for ways to use more RAM if it will provide a benefit to the end user. What they are doing is optimizing expensive resources, like your CPU, and HDD accesses. And your time! RAM is not an exensive resource.


Hope this helps!

iMac, Mac OS X (10.6.8), 2011 - 27" SSD + HDD 12GB

Posted on Aug 4, 2011 10:13 AM

Reply
69 replies

Aug 5, 2011 10:56 AM in response to John Kitchen

The advice is good, thanks for that. But I totally disagree about your definition of "small memory Mac". Apple TODAY sells most of their Mac with 4GB of RAM, this must be considered a sufficient amount of RAM to work with with the software they sell the computer with (Osx Lion). Moreover, machines like the most modern Macbook Pro can upgrade just to 8 GB of RAM, so you can't consider it a minimum (sometimes insufficient)... it's the maximum! Here there's a bug (and it's big) and Apple has to fix it, otherwise they have to change the name of Macbook Pro in Macbook (without "Pro") because a Pro machine which cannot run Pro applications without problems is not Pro.

Aug 5, 2011 11:44 AM in response to walter86

Walter


Thanks for the positive comments!


I'll have to push back just a little on the semantics. When I say "small memory Mac", I mean those which do not need 64 bit addressing, either in the OS or the apps. 32 bits is sufficent to address 4GBs of RAM, so I class 4GB Macs as "small memory". This is not an insult to them, it's just my way of differentiation.


In an 8GB Mac, it might be rare that it would be appropriate to have an app consuming more than 4GBs, since the OS and other processes and apps will probably not leave much more than 4GBs for a single app. So I conclude that in most cases, 32 bit addressing will be sufficient for most apps. Hence, I suggest that 8 GB Macs are probably "small memory".


With 64 bit addressing, the limit of addressibility is raised to 18,446,744,074 GBs which is quite a lot larger than any Mac today! Relative to that number, we might say all 2011 Macs are "small memory". 😁


This is the argument behind my justification for recommending the use of 32 bit addressing for key apps. Unless you have 8 GBs of RAM or more, you just don't need 64 bit addressing.


You suggest that 4GBs should be enough to work with OS X Lion, and for many it is. But not for all. That is why the 2011 iMac can be expanded to 32GBs and Mac Pros even more. If everything could fit in 4GBs, then there would be no need for larger RAMs.


Some people find that an 8GB MacBook Pro is suffient to run Pro applications, but remember that a MacBook Pro is still a laptop computer. It's not a Mac Pro, which is where the Pro apps are probably happiest, although the iMac is now up in that range. And recent MacBook Pros are too, now that they can take up to 16GBs.


But earlier MacBook Pros, such as mine, are stuck with an 8GB ceiling, so I have to be careful

Aug 5, 2011 12:39 PM in response to John Kitchen

For what it is worth, I took the following steps on my mid 2010 27in iMac and it is working flawlessly under Lion, including Aperture.

1. repaired permissions in Aperture

2. rerpaired (not rebuilt) Aperture database

3. set Aperture to be 'assigned' to 'none' desktops by selecting options in the dock. This solved the fullscreen issues

4. GOT 8gig more ram for a total of 12. Wow that made a huge difference. My machine runs very smooth and very quiet now. Aperture runs like a dream.

The ram was the best 80 buck I've spent in a while.


Will

Aug 7, 2011 12:24 PM in response to etresoft

Almost always in software where a new release comes out there is a general tendncy for the developers to use more memory when building new features and better ways to do things. These changes almost always override any new virtual memory tricks or low level efficiencies. I changed from snow leopard to lion and although most of the programs tend to run a bit faster once in place and in a full screen window like the iOS system uses, the startup time is quite a bit worse. I can handle it, but because many people tend to finish up by quitting a program and removing the virtual full screen window automatically allocated to thse IOS like features, Lion seems slower. Also there is a maximum if 16 virtual full screen windows so it is not really practical to leave all of the full screen apps running. If I were Apple and wanted the user experience to be better, I would not fix the maximum number of full screen apps and let the virtual memory manager deal with those that are not used instead of stopping at 16. This limit is so much more like Microsoft when they ran out of windows in Windows 3.1.1 and other earlier versions. The UNIX kernel should be able to handle the pageouts. In the end more memory is always faster as programmers always are faced with the tradeoff between memory and speed.

Aug 9, 2011 10:23 AM in response to dwb

If a user's computer is slow under Lion but wasn't with Snow Leopard, before adding more RAM, the first thing to do is make sure the user has a solid Lion installation. The upgrade method Apple has chosen to use leaves too many incompatible (not crashing incompatible, mind you, just not Lion ready) plug-ins, services, contextual menus, etc. Get that taken care of, make sure the user has up-to-date software and drivers and often that slow Lion computer has begun to purr. And frankly, sometimes the only solution is to erase the drive and install Lion on an empty drive.


Can you be more specific about what the best way is to find and disable "incompatible plug-ins, services, contextual menus"?

Aug 9, 2011 1:06 PM in response to dlehman

Can you be more specific about what the best way is to find and disable "incompatible plug-ins, services, contextual menus"?

Inside both your Library folder and the root level Library folder you'll find folders called Internet Plug-ins, Contextual Menu Items, Input Managers, Services, and Input Items. The Contextual Menu Items & Services are probably not going to slow your computer down but they can still be outdated and cause stability issues when you try to use them. Rather than delete them all out of hand, I created new folders adding disabled to the end of each (in other words, Internet Plug-ins disabled) and moved all the files there that were older than the creation date of Lion. Then, using the name of the files I moved, I looked for new versions and installed them. So I installed a new updated version of Flash for example. After restarting my computer was noticeably faster but since I hadn't been able to find new updates for everything I removed, I slowly added items back (I colored them using labels to keep track of what I added) and restarted. It didn't take me terribly long to do this and in doing so an installation that hadn't gone terribly well turned out to be successful without costing me another $70 for RAM.

Aug 10, 2011 7:35 AM in response to John Kitchen

I have a 4GB MacBook Pro, and I came up with a hack which helps greatly with the battery/temperature/memory issues that show under Lion.


The following thread describes my hack: two versions of an AppleScript-based fix and one version of a launchd-based fix ... I now recommend the latter.


This is very detailed, geeky stuff ... but it works for me to autmatically free up memory and keep the battery/temperature issues at a manageable level, without my having to add more memory to my machine.


YMMV, but good luck: https://discussions.apple.com/thread/3248102?answerId=15882892022#15882892022

.

Aug 10, 2011 7:51 AM in response to John Kitchen

booting Lion in 32bit mode on machines with under or equal 4GB is generally faster compared to 64bit mode while booting the 64bit kernel with MORE then 4GB is faster:



Running 64bit apps on 32bit OSX is not a problem. In Snow this behaviour was standard. The 64bit Kernel just cannot use 32bit only drivers. Drivers included in Snow and Lion are hybrids : 32 and 64 bit capable, so depending on which kernel is booted the correct drivers is picked up on boot.


For Lion Apple sets the booted kernel to 64bit per default. This is the biggest change because Snow always booted into 32bit mode, but alas it can be reverted and you lose nothing.


While it is true that 32bit Operating Systems have a 4GB barrier, Apple uses the PAE ( physical adress extension ) trick : in PAE mode the Ram above 4GB will be accessed by re-adressing the available space. This can, but must not have necessary performance-issues. having Ram like 8,16,32,64 GB of Ram of course would only effectively used by booting the 64bit kernel which can adress all the Ram in one space without any tricks.

Aug 10, 2011 7:57 AM in response to dwb

Aperture3.1 ( native 64bit mode , no plugins from 3rd parties ) with the latest update ( 3.1.3 I think ) applied under Lion is faster loading and processing then on Snow with the same update. On 4GB with 32bit boot for me MBP5,1 late 2008 and even more noticable on iMac 27# late 2009 ( also 4B ) .

Aug 11, 2011 9:13 AM in response to pvcooper

Back in the days of Archive & Install (which I believe Apple should never have dropped) Apple did remove items - lets call them unproven plug-ins etc. However since there are so many applications that dump things into both the user Library and the root level Library Apple had to err on the side of caution, quarantining things that weren't known safe. Users cried foul because their beloved plug-ins etc didn't work - they weren't loaded - and then howled because they were expected to dive into the Previous folder and figure out what could safely go back.


Apple can't win - it is darned if it does and darned if it doesn't. Based on my non-scientific survey (the number of users who have come to me for help) the problem isn't as big as it appears here on the support community. With at least 1 million upgraders, even if only 1% had upgrade problems, that's a lot of people coming here to complain.

Lion and Macs with 4GBs of RAM (or even 8GBs)

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