I'm a designer using Snow Leopard on a MacBook Pro 15" (i7) with 8GB Ram, 500GB (180GB free) (2010 model).

I usually use Chrome (4/5 tabs), Firefox (1/2 tabs), Skype, VM Ware Fusion (with Win XP, using only 512MB), Photoshop CS5, Adium, iTunes, maybe Filezilla.

Photoshop is the main Ram user. It can eat up to 3GB or more as time rolls by, and I'm not working with very big files, 50mb max, and only 2 or 3 open.

When I start opening programs everything works fine. It's later on that you see that you have very (and I mean veryy) little Free Ram left. Between 8MB and 15MB. At the same time I have 2.21 GB of Inactive Memory.

The machine gets much slower once you get below 150MB of Free Memory, and it's a total lie that Inactive Memory gets released onto other programs to overcome this slowness. It never gets released until you close the program.

I wanted to post a screenshot of my Activity Monitor but your site doesn't allow it if I'm a new user.

Once your Free memory gets to these levels (15MB), the Page Outs start increasing and the Inactive Memory never gets released. It gets laggy.

Please don't tell me that a 2010 Macbook Pro with 8GB is not enough to work with Photoshop on small to medium sized files. Normal users (internet, skype, movie watching, etc.) won't have this problem, but if used for design or more heavy tasks (which I believe is this machine's main purpose), it doesn't work properly.

I think this is a very important issue that has never been addressed. I don't know if Mountain Lion has solved this, but I've searched around and haven't read good comments (they even say it eats up more Ram).

Do you know if a MacBook Air i5/i7 8GB 256GB SSD will improve on this matter? Do SSD's improve Ram usage? I'm planning on changing the MacBook Pro (not because of this, because of it's size).

Here's the complete Terminal response from the command top -o rsize -l 1 -S -n 10:

Processes: 92 total, 3 running, 1 stuck, 88 sleeping, 515 threads
2013/03/08 17:33:05
Load Avg: 0.24, 0.28, 0.28 
CPU usage: 5.55% user, 27.77% sys, 66.66% idle 
SharedLibs: 5796K resident, 4760K data, 0B linkedit.
MemRegions: 22354 total, 4549M resident, 42M private, 1359M shared.
PhysMem: 1322M wired, 4587M active, 1908M inactive, 7817M used, 372M free.
VM: 183G vsize, 1041M framework vsize, 558408(0) pageins, 418(0) pageouts.
Swap: 34M + 222M free.
Purgeable: 81M 183(0) pages purged.
Networks: packets: 235338/116M in, 224406/115M out.
Disks: 135805/3530M read, 131663/2361M written.

296   Adobe Photoshop  0.0  15:12.94 17   1   447+   1754+  3349M+ 263M+ 3547M+ 3612M+ 6934M+ 296  144  sleeping 502 1119232+  8721+  56249389+ 27765125+ 2528538+  61681638+ 3147104+  29186+  owner        
341   vmware-vmx       0.0  12:24.49 23   1   216+   402+   19M+   629M+ 711M+  60M+   3509M+ 341  1    sleeping 0   479594+   724+   373320+   92479+    17797849+ 296216+   10285249+ 166343+ root         
0-    kernel_task      0.0  10:08.35 73/4 0   2+     1023+  76M+   0B    368M+  128M+  3144M+ 0    0    running  0   37759+    0      78790277+ 73869135+ 0         0         17309424+ 0       root         
254   firefox          0.0  04:08.53 29   1   255+   4957+  204M+  238M+ 321M+  303M+  4025M+ 250  1    sleeping 502 1399145+  67635+ 6542552+  3242741+  720602+   7063491+  537809+   7020+   owner        
276-  Skype            0.0  15:06.50 33   2   602+   932+   99M+   110M+ 159M+  166M+  1163M+ 276  144  sleeping 502 23219202+ 5402+  7363050+  3682250+  1338611+  8832162+  1493925+  6289+   owner        
236-  Google Chrome    0.0  04:30.67 31   1   363+   483+   109M+  114M+ 145M+  323M+  1353M+ 236  144  sleeping 502 937175+   29790+ 6074380+  2834369+  3647085+  7080110+  1273550+  45988+  owner        
66    WindowServer     0.0  07:55.98 7/1  1   440+   1405+  15M+   195M+ 136M+  76M+   3197M+ 66   1    running  88  12073018+ 4795+  3927394+  1339534+  3060626+  5647891+  2244590+  2527+   _windowserver
417-  Google Chrome He 0.0  00:24.08 5    1   97+    385+   83M+   85M+  132M+  164M+  1169M+ 236  236  sleeping 502 91462+    1381+  181063+   92181+    155361+   211895+   43893+    13933+  owner        
280-  Google Chrome He 0.0  01:05.81 9    2   103+   380+   97M+   80M+  128M+  190M+  1173M+ 236  236  sleeping 502 162474+   1378+  1519179+  772658+   557874+   1822614+  241725+   33033+  owner        
3425- Dreamweaver      0.0  00:28.24 12   2   193+   961+   51M+   150M+ 110M+  105M+  1263M+ 3425 144  sleeping 502 51623+    2346+  977727+   459446+   142689+   1400204+  228438+   104+    owner
  • Inactive memory are memory "blocks" that an application has request but either not use or the application has not actively used this memory area. The OS marks this zone as inactive and if needed this zone has a higher probability to go into the swap file than others, although this is only one factor in the algorithm that OS are using to guess what to put in the swap. So yes, once the system has no free memory left, it will start paging out (putting into the swap) some memory zone and it will get laggy. SSD could improve swaping performance, but not RAM usage.
    – Huygens
    Mar 7, 2013 at 21:40
  • 2
    As you cannot upload a screenshot, and anyway it might also be easier to see, could you execute in a terminal top -o rsize -l 1 -S -n 10 and paste in your post the result? The command print the information for 10 processes of the top command which list processes, and it sorts this process by resident memory size.
    – Huygens
    Mar 7, 2013 at 21:51
  • 2
    SSDs have no effect on RAM usage, but the speed with which memory can be paged to and from disk is so much greater. My 4GB RAM Air feels much snappier while under memory pressure than my wife's 4GB RAM Pro with its mechanical disk.
    – Dan J
    Mar 7, 2013 at 21:57
  • Hi, thanks for your replies! I'll paste Terminal's results in a question below, not enough space here.
    – Jimmy
    Mar 7, 2013 at 22:36
  • @Jimmy it would have been useful to have the complete top output, including the top 10 memory hungry processes. Without this information, no real help can be provided. There are a couple of outstanding information though, you have more than 1GB wired memory, another 1 GB of shared memory and are actively using more than half of the total amount of memory. I cannot draw hypothesis as long as I do not see the top 10 processes.
    – Huygens
    Mar 8, 2013 at 7:51

4 Answers 4


My experience with inactive memory is similar to yours and as soon as free memory approaches zero, performance takes a big dive. An SSD makes a big difference, not because of RAM usage or even because it improves paging speed, but because it makes it very fast to restart a program and release the "extra" memory it's using. I don't use Photoshop and VMware but Firefox, Safari, and Chrome are all memory hungry and don't appear to ever release memory once they grab it so restarting any of them usually is a quick fix.

Memory usage in Chrome is not as obvious as others because Chrome runs as many separate processes so you don't see a single big number for memory usage.


Photoshop takes 70% of your RAM by default when it starts. Whether it's a 2G RAM or 64G RAM machine, Photoshop grabs 70% of the RAM. When calculating how much space Photoshop is wanting for files. look at the document sizes in the lower-left. I believe the second number is how large the file is when open. That can be a much different size than the first number of how much disk pace a file takes. a 50MB file can easily open up to want more than 500MB of RAM. As it fills up and uses all your RAM, Photoshop starts using Virtual Memory, Page-swapping to work on files.

But at the same time, so is VM Fusion. While it's only set for 512MB RAM for the XP, it's also using it's own VM-Scheme in the background. Switching back and forth between those apps will always result in lags while each one give up Virtual-Memory, and takes on Virtual Memory. This will result in lagginess all the time.

Best bet is to have either one or the other open, but not both, and 8G of RAM for PS6 is OK, but my next lease refresh of 35 Macbook Pro's are all going to have 16G RAM, it's quickly becoming the minimum you want for PS6. I don't know what changed between 5.5 and 6, but all my users really started complaining about speed after I rolled out CS6 onto their machines.

SSD's are helpful in performance because they are a lot faster than HDD in dealing with Virtual Memory I.E. page-swapping....

  • Thanks Robert. It's really a pain to work like this. Even my Dell desktop at work with win XP (3gb ram) is snappier sometimes (although the more you use Photoshop, the slower it gets).
    – Jimmy
    Mar 8, 2013 at 0:12
  • If this answer solved your question, please mark it as accepted by clicking the tick next to it :)
    – Emil
    Mar 8, 2013 at 21:51
  • 1
    @Robert I've also realized that the more layers you have inside a Psd file (and I mean many layers in a 50MB file) the slower it gets to drag objects throughout the canvas. Do you think this is caused because of the slow speed of the 5400rpm hd or due to the fact that too many layers always cause this behaviour (no matter what machine you have)? (in this case I have 2GB of free ram, so Ram is not the issue). Thanks, Jimmy
    – Jimmy
    Mar 12, 2013 at 20:51
  • Not sure, but a 5400 drive would not help the situation. As soon as Photoshop starts using it's paging or VM file, you are hosed. Especially with a 5400 drive. (are there any slower drives anymore?) The minimum specs i request for the Creatives are: Core i7, at least 7200 drive, SSD if i can get it. Storage is not the issue as they can keep their work on our Fileserver, and 16G RAM. That should be good for the next 3 years (the length of the lease) It's worth it in the long run..Especially if you are going to be paid for Photoshop work.
    – Robert
    Mar 12, 2013 at 22:03

Start up a terminal and enter purge to free inactive memory. You need to do this every time your free memory reaches nearly zero.

You can also use the $4,99 app iCleanMemory from the Mac App Store. It puts an indicator in your menu bar that shows free RAM, and when you click on it, a button shows up that executes purge, for easy acces.


I agree. The memory is not released and I had to sometime do multiple restart to get it released and speed restore back to normal.

  • Welcome on Ask Different! This should be a comment and not an answer. Once you have 50 reputation you can post comments. In the meantime you can't post comments. :-( I'm sorry, I didn't make this rule! :-( Please do not use answers as comments.
    – jobukkit
    May 8, 2013 at 7:56

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