PowerMac G4 PCI (Yikes!) RAM compatibility

I recently acquired a 512MB DIMM of PC-100 RAM and put it in a Yikes! G4. I got it to boot up once, then afterwards it would turn on but not boot.

Before: 256+128+128+128
After: 256+512+128+128

(where the first (256) is the innermost slot, furthest from the top edge of the case door)

In the "After" configuration, the OS only reported half (256) of that DIMM. I tried it in other slots, with and without some modules, but it would only turn on, not boot.

The DIMM has Samsung chips, k4s560832d-tc75. Google seems to think of this as registered RAM, yet this DIMM (I'm told) was running fine in an iMac 500MHz for several months.

Am I out of luck?

I have a 350Mhz G4 Yikes here in my Mac collection. They were not made to support 512Meg Dimms. I tried several just to be sure and all did what you are seeing. If there were other dimms, 256 Megs would show up for that 512 Dimm, but if the 512 was in there alone it would not even chime. A lot of older computers will not support 512Meg Dimms. I have an Asus CUBX with Pentium III Copermine, and it will only support 256 Meg Dimms.

The Yikes will accept 4x256 meg Dimms for 1GB RAM. The Yikes used basically a G3 motherboard with the G4 CPU and some changes. It did not even have an AGP slot like the Sawtooth that followed it. The Sawtooth G4's support 512 Meg Dimms. I have one with 1.5GB ram.

http://www.lowendmac.com/ppc/g4.shtml

Thanks, the incompatibility you cite is what others tell me on other forums, as well as Kingston and Corsair's RAM choosers (but not Crucial's, rather unsurprisingly). Guess I'll try and trade this for a pair of 256s out there. Thanks again.

Anyone know if this G4 will accept PC-100 ECC RAM? I have an offer to trade but I don't know if the board will cope with it. I also don't know whether the RAM is registered, or it the board will cope with that.

sm8000 said:

Anyone know if this G4 will accept PC-100 ECC RAM? I have an offer to trade but I don't know if the board will cope with it. I also don't know whether the RAM is registered, or it the board will cope with that.

Click to expand...

Almost certainly not. There's a slim chance it will just ignore the 9th bit and work, but apple usually states "must not be ECC, must not be Registered"