manage app RAM use

Is there a way to put a threshold on the amount of real memory a application can use? I noticed my firefox is running ~400MB with a few tabs open and still then even after I closed all but one tab. and I was wonder what the same program would do on a 512MB system, surely the program makes better use of the RAM allowed, its like its a % base or something that it goes by.

OSX 10.6.8

Traditionally, no there is no way of limit the amount of memory an application uses. If you Google this topic, you'll see mentions of using 'ulimit' to control certain aspects of memory consumption, but most of those don't control the maximum.

As an application uses up all free memory, if it continues to ask for more memory, then you'll begin to start to swap to disk to make room for the new memory requests and this usually has an adverse effect on your system performance as the amount of swapping increases causing disk thrashing whereby things are sent to the hard drive and brought back as apps needs them and back and forth..

When you have less RAM, applications are a little more restrained. Firefox also tends to be a bit of a memory hog especially if you have quite a few extensions installed.

My iMac has been up for 4 days now and I've had Mail, Chrome, and iTunes running for all this time and their %CPU and Threads and Real Mem is:

Mail ashwin 0.0 13 332.5 MB Intel (64 bit)
iTunes ashwin 0.1 36 281.3 MB Intel (64 bit)
Google Chrome ashwin 0.3 30 216.6 MB Intel
Google Chrome Helper ashwin 0.0 5 29.7 MB Intel
Google Chrome Renderer ashwin 0.1 6 74.8 MB Intel
Google Chrome Renderer ashwin 0.0 6 198.4 MB Intel
Google Chrome Renderer ashwin 0.0 6 259.7 MB Intel
Google Chrome Renderer ashwin 0.0 6 80.9 MB Intel
Google Chrome Renderer ashwin 0.0 6 85.5 MB Intel
Google Chrome Renderer ashwin 0.0 6 62.2 MB Intel
Google Chrome Renderer ashwin 0.0 6 50.5 MB Intel
Google Chrome Worker ashwin 0.0 6 63.2 MB Intel
Google Chrome Worker ashwin 0.0 6 85.8 MB Intel
Google Chrome Worker ashwin 0.0 6 42.5 MB Intel
Google Chrome Worker ashwin 0.0 6 36.0 MB Intel
Google Chrome Worker ashwin 0.2 6 105.7 MB Intel
Google Chrome Worker ashwin 0.0 7 62.1 MB Intel
Google Chrome Worker ashwin 0.0 6 73.8 MB Intel

My system has 16 GB of memory and I stil have 8.66 GB of memory to go..

My current Firefox:



only two tabs have been opened.