OS XLion - heavy memory usage


I am wondering whether the memory use I see is common to the Mac OS X - touted as the graphics pros choice - it's seems anything but to me.

I have a mid 2010 iMac 27"

3.2 GHz Intel Core i3
12 GB 1333 MHz DDR3
ATI Radeon HD 5670 512 MB
Mac OS X Lion 10.7.4

That spec should be more than ample. No.

Pixelmator uses up to 5GB yes - GB) just opening the app. If I dare to open an actual image - let's say a 120mb jpg for editing - the memory usage is even higher - usually resulting in the image not opening at all.

GIMP is similar, but not as extreme - opening the file uses around 2GB.

Nevertheless, both of the above seem to me to be examples of excessive memory usage. Certainly, my machine slows to a crawl when doing anything related to images - pretty hopeless really.

Pixelmator developers ask for buckets of info (supplied) but no solution.

So, my question is, is this type of memory usage common for the Mac OS X?

If it is, it is, clearly, not the wonderful graphics solutions touted by Apple and it's followers.

NB. I am a very experienced user of PC's and fairly new to the disappointing world of Apple.

Any feedback welcome,


First run soft cache clearing on your Mac. Download either Yasu or Onyx and run the cache cleaning routines.

Run all the cleaning routines and let the software reboot your Mac. Then after that software reboot immediately manually reboot. This will rebuild your startup/shutdown system cache.

Lastly are these programs up to date or older versions?

Goo Luck.
It's a good choice to make sure that the major apps that you use are up-to-date, as that may often include bug fixes for use with your current OS X system.

Some processes may use a lot of RAM but, unless you see actual performance issues (and it sounds like you do), then memory use, by itself, is simply a normal result. Dramatic slow-downs, to the point of crashing, perhaps, is not normal - so you need to investigate to hopefully discover what is taking huge amounts of processor time, which could be something other than the apps that you are choosing to run at the time.
Watch in your Activity Monitor when you open Pixelmator or Gimp. You may find that you are having pageouts, and you can also sort the list of processes by CPU use. That may help you decide what is really taking all that memory, and giving you performance issues. Be sure to change the drop-down in Activity Monitor, so it displays All Processes, and not just My Processes. Click the process menu header to sort by the particular criterium, such as CPU, or number of threads, for example. You can click on the tab for System Memory (in the bottom part of that window) to monitor memory use for your overall system. How much free memory is there when you get those slowdowns, and do you also get page-outs? I think you should almost never see any page-outs with the amount of RAM that you have installed. Cleaning out the system soft caches may also help with that.
120mb jpg

120MB JPEG file would equate to an image that is many, many times that size. In other words, working on a 120MB JPEG file is akin to working on a TIFF or RAW file that is an upward of 600MB to 2GB in size.

It stands to reason that Pixelmator and GIMP would use up to 5GB of RAM in order to work on this absolutely massive image. I don't see anything out of the ordinary with that RAM usage with that image file.

Your system slowing to a crawl after doing this is, decidedly, not normal with 12GB of RAM installed. Might be an unrelated problem. How full is your hard drive?

...touted as the graphics pros choice...

Who touted this to you? Sounds eerily similar to "Macs are good for graphics and PCs are good for spreadsheets" which is an old, outdated, and inaccurate generalization.