Memory Culprit?

[Franck]

I've been plagued by Random Kernel panics.  My DP 800 G4 would run like 
a charm for weeks, then out of the blue, it will start crashing with 
Kernel Panics.  I'll repair permissions (one out of two runs would 
crash), run fsck, run drive 10, disk defrag, mac Janitor, you name it.  
Kernel panics still happen randomly.
Suspect # 1: Memory.  I've ran Apple Software Extended memory Test on 
my 1024 mb of ram (three chips 2-256, 1-512), it passes but I've 
noticed that the memory profiler indicates that 2 chips are 10.0 cycle 
n.s and one is 7.5 cycle n.s.
Could that difference in rating be the problem? Anyone on the list 
could explain what it means?  In advance thank you.