MAC OS X Lion performance problem - broken memory management

Starting with OS X 10.5 there are evident memory management problems in MAC OS X. The web was already then cluttered with complaints about system slowing down dramatically after some time. Back then i had slower machine, Mac Mini with 1GB RAM, so i (wrongly) concluded that it was due to inferior hardware.

Now i have 2010 MBP, core i7, 8 GB RAM, dual GPU.

Mac os X Snow Leopard was pain, but after migrating to OS X Lion, working some serious stuff on MAC started to be a nightmare.

I finally managed to reproduce the problematic scenario, so i run the test and recorded the screen, into video.

http://www.youtube.com/watch?v=u5wZwZh61_4

I run the tar+bzip command, which is basic unix stuff, on the large amount of picture files, in my Pictures/ folder. Just before start, i run the "purge" command, to delete inactive/cached program data.

You can see on the video that free memory starts to drop very fast, and inactive is constantly rising. If you take a look at "bsdtar" command, it takes only a fragment of RAM, so the problem is not in this process. You cannot say that it is a program memory leak, because then the problem would not be in inactive ram, rather in active/wired.

When the free memory dropped below 100mb, i started some apps, like Safari, iPhoto and MS Word, and you can see in the video, that it takes even minutes ⚠ to start an app, when normally (when there is free RAM), it would take some 3-5 secs to load.

I run the same scenario and the same commands on my Linux Centos 6 box, no problem there ! Memory usage is some 10-20mb, no problems with cache/buffer.

The memory management must be very broken in Mac OS X !