On Dec 26, 2008, at 6:03 AM, Beniamino Cenci Goga wrote: > I replaced the 266 MHz G3 with a 450 MHz G4 and changed the jumper > position to get a 83.3 MHz bus x 5.5 = 458 MHz G4.
You need to look at the Grackle chip on the motherboard to see if it can support the 83MHz bus speed. There were two different Grackle chips used on various G3s, some were 83 MHz and some were only 66 MHz. The Grackle chip is the blue tinted chip just behind the CPU. If the final numbers on the chip end in 66 then it's only a 66MHz chips and normally can't be overclocked to 83 MHz without problems. For example, my 266 Rev.B has a Grackle with # XPC106ARX66CG, with the "66" between the X & C being the ones that tell you it's a 66MHz chip. Your chip would need to have an "83" there instead of a "66" to overclock it reliably. > The G4 chip I am using has a bad L2 cache, nevertheless I wanted to > try again to enable > it so I kept trying all known cache enablers. The result was a very > bad crash. How did you know the L2 was bad? I believe in OS 9 there should be an error message at boot that tells you it's bad? There is no similar message in OS X, but System Profiler in OS X should say "0" for the size if it's bad. If the L2 is bad, you're probably better off with the OEM G3 chip, or get a working G4. Bad L2 is S-L-O-W. > After that I can only boot off the OS 9 CD, format the HD (I have > tried two HDs, the original and a known good one pulled from a > Yosemite), install OS 9, but at the subsequent reboot the HD is no > longer recognized. > > Pretty weird. Now I am going back to the G3 processor and see what > happens. Any ideas? Think you've got jumpers set too high. I'd try a 66 MHz bus again unless you can confirm you've got the required faster Grackle chip. On the 66 MHz bus you'll need to run either 433 MHz or 466 MHz for the G4. If it's a true 450 MHz CPU you should be able to run 466MHz without problems using a 66 MHz bus. Benchmarks have shown that the real gain in going from a 66 MHz bus to an 83 MHz is very small, much smaller than the ratio of the speeds. I think this is because the ATA bus is 33 MHz and is sync'd better to 66 MHz than 83 MHz. I think the gain is less than 5%. You can run 10.4.11 on the Beige, but that subject belongs on the Unsupported OS X list rather than G3-5 list since Beige OS X support ends at 10.2.8. To subscribe to Unsupported OS X group, send email to: [email protected] --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed Low End Mac's G3-5 List, a group for those using G3, G4, and G5 desktop Macs - with a particular focus on Power Macs. The list FAQ is at http://lowendmac.com/lists/g-list.shtml and our netiquette guide is at http://www.lowendmac.com/lists/netiquette.shtml To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/g3-5-list?hl=en Low End Mac RSS feed at feed://lowendmac.com/feed.xml -~----------~----~----~----~------~----~------~--~---
