[G4] upgrade problems (gigadesigns)

[andrew steele]

I just got a used gigadesign g-celerator 900-1.5 MHz processor, I’m running 
a old g4 sawtooth (400mhz)

I keep getting the following problems

1Built in memory detects a problem with L3 cache
2Constant freezing

it's currently clocked at 1k MHz, but it came clocked at 1.5kMHz

Could the problems I'm having be from overclocking the last owner did or 
something I'm not doing right?