Graphic problems in OSX with following Crash

Question

Hello
got my MacBook for one week and experience repeating very frustrating crashes with the same pattern.
After working for several hours with the Book the shadow of several Applications start beeing not rendered properly as semi-transparent gradient anymore but instead as opaque stripes (see picture below). In the following hour more and more Applications start behaving like that.
This goes on until at some point (sometimes earlier, sometimes later) the Systems hangs. That is to say every Application (except iTunes which continues playing smoothly) gains probably only a half percent cpu time (i.e. one crash happened while starting eclipse - after 15 minutes not even 10 percent of the loading statusbar had shown - though the program normaly needs only 5-10 secs to completely load)
My first thought was that this is an OSX related problem so I reinstalled OSX - problem occured again.
So I opened the Terminal with top and waited for the next 'crash'. top showed me an overall CPU usage of 5% - though the laptop was not usable at that point anymore.
Next idea was that there had been damaged RAM in the device (which would explain the graphic problem since the system RAM is the same as the graphic RAM). So i wrote a python script which produces a matrix consuming all available RAM and processes endless matrix operations cycling through the allocated RAM blocks while doing this. After 4 hours of nothing happening I stopped that.
However it has been several years I had my last mac so I installed Bootcamp and run the same script in Windows again - knowing that Windows would immediately crash with a kernel panic once a RAM problem occurs. But 4 hours later nothing happened. Also a test in 3DMark did not take down the computer.
So I reinstalled OSX again thinking it might be something like SIMBL or another app which deep systemcalls. I reinstalled a vanilla OSX (10.4.6) which came with my MacBook and only installed the Applications I mostly require for working (the MacBook is my only computer) - TextMate, Maclipse, MacPython, XTools, PathFinder (the last one for convenience though ).
And the crash came again.
Afterwards I looked through the Console logs but haven't found anything unusual (at least nothing looking suspicious judging from my linux experience).
At the time of the crash which happened after I took the picture only iTunes, TextMate and the Finder where running (and had been from the starting time of the system).
I don't know what to do anymore. If someone has any helpfull suggestion, thoughts, or related ideas please share them with me.
thanks in advance.
MacBook (2GHz, 512MB) - 4H622xxxxxx   Mac OS X (10.4.6)  

Answer 1

Seems this is a widespread problem so I close this thread in favour of the existing one, accessible at:
http://discussions.apple.com/thread.jspa?threadID=489831&start=0&tstart=0
MacBook (2GHz, 512MB) - 4H622xxxxxx   Mac OS X (10.4.6)