iBook G4 chipset failure causing segfaults?

[Bruce Cran]

I've recently found that my G4 iBook is causing programs to segfault
when they start going into swap: the effect is worse on -current but
I'm also seeing it on 7.2. For example, if I run a program to allocate 500MB the
system will swap out most programs since I only have 512MB RAM. After a
while dhclient and sendmail segfault while the test program keeps
running; I've also seen tcsh and login segfault too as I logout. I
originally found the problem when building clangbsd, where 'as' would
segfault when it started building the large C++ files that come with
clang. I can run a normal buildworld so I guess this is more of a
problem with the chipset (caused by swapping?) than a memory problem?

I've run the Apple Hardware Test utility over 30 loops without any
errors - has anyone else seen this problem, and is it likely that the
hardware is simply starting to fail?

-- 
Bruce Cran