Bad RAM

i was just on the MacFixIt.com website and i saw this post about Bad RAM on the new Powerbooks. has anybody encountered this problem? what exactly does it entail? and how would one identify "bad" RAM? thanks.

OS X is more sensitive to bad ram than any other OS (mac or PC) that i have ever seen. I do tech support for a university and work with both PCs and Macs. A couple months ago i setup two brand new g4 mirror dualy 1.25 (as i remember). Both proffs wanted VPC XP but only had 256 RAM so i suggested they each get a 512 stick... both turned out bad. In both cases the machine became VERY unstable.... I have used all the released OS X versions and 10.2 and after i have seen to be very stable. Well, stick a bad RAM stick in and that will change... also apple hardware test (hold option key to startup with OS install cd in) gave a kernel panic in both cases when the detailed test was run. Returned the sticks, got new ones that were fine.... note: the larger the RAM stick the harder it is for the manufacturer to test.... the number of possible states increases exponentially,