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Best way to test 15+ PowerPC G3 and G4 Ziff processors


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Sometimes I don't know what I'm getting myself into.  I picked up a quantity of 15+ PowerPC G3 and G4 processors of the same ZIFF socket type.  The same type used in the G3 beige, G3 B&W, and earlier G4 models.

 

I want to find the easiest and safest way to test them all.  I do happen to have an XLR8 Carrier Ziff CPU-Slot upgrade card, but I don't want to blow it up.  I also have a very nice condition beige G3 Mac, and a presently non-working G3 B&W.  Can G4 CPUs be tested in the Beige G3/XLR8 Carrier Ziff safely?  Should I buy a G4 just for testing these things out?

 

Thoughts ?

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I'd look for an affordable Beige G3 motherboard.   They can be used with an ATX power supply.   However, you need to make sure you get the ROM DIMM and the voltage regulator module -- and probably the heat sink for the CPU module.

 

If you find one lacking a ROM DIMM I can send you a Rev. A for the cost of shipping.   I found a couple in an anti-static bag a couple of days ago.  Rev. A doesn't support Slave drives on the IDE ports.

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It would be hard to test G3 ZIF processors made for a B&W with 100FSB on a beige G3 motherboard that does 66 fsb. You would also have to update the firmware on a B&W G3 to be able to test a G4 (no idea about suing one in a beige G3).

 

 

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I haven't tried a G4 ZIF in a Beige G3 but I am using a 350mhz one from a B&W, slightly overclocked to 366mhz. I've read lots of postings from people using a G4 from a Yikes in their beige G3 but I haven't had a spare CPU and I haven't wanted to bother pulling one out of a Yikes just to try it out.

 

I'd probably test the ZIFs in the Beige G3 as it'd be a little faster than with the carrier. I wouldn't bother changing the jumpers for the test as I'd be looking to see if they work and underclocking isn't harmfull.

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10 hours ago, waynestewart said:

I haven't tried a G4 ZIF in a Beige G3 but I am using a 350mhz one from a B&W, slightly overclocked to 366mhz. I've read lots of postings from people using a G4 from a Yikes in their beige G3 but I haven't had a spare CPU and I haven't wanted to bother pulling one out of a Yikes just to try it out.

 

I'd probably test the ZIFs in the Beige G3 as it'd be a little faster than with the carrier. I wouldn't bother changing the jumpers for the test as I'd be looking to see if they work and underclocking isn't harmfull.


Thanks for the advice, waynestewart. If there are issues with the CPU is there any great possibility I could ruin my beige G3 motherboard by installing it and booting or is it more of a “if it has problems it just won’t boot”?

 

Also what are the possibilities of testing the G4 chips on the beige G3?

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While I can’t guarantee it, I think it’s extremely unlikely that you’d damage the G3.

I was thinking about the fact that I’d never tried a G4 in a Beige G3. The beige G3 is handy, the Yikes G4 is handy, lets give it a try. Did it and the Beige “G4” booted up. System profiler recognizes that there’s now a G4 processor in it. Unfortunately the G4 ZIF has to go back to the Yikes.

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Which voltage regulator card is in your beige G3? I've heard that one from Royal Technology can misbehave with certain ZIF upgrades, possibly causing damage.

 

If you have the Switch Power or Raytheon voltage regulator card, you should be fine.

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On 1/9/2021 at 4:09 AM, androda said:

Which voltage regulator card is in your beige G3? I've heard that one from Royal Technology can misbehave with certain ZIF upgrades, possibly causing damage.

 

If you have the Switch Power or Raytheon voltage regulator card, you should be fine.


I was not aware of this. Which is why I asked first. I’m very glad I asked. Thanks!

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On 1/9/2021 at 3:49 AM, waynestewart said:

While I can’t guarantee it, I think it’s extremely unlikely that you’d damage the G3.

 

I was thinking about the fact that I’d never tried a G4 in a Beige G3. The beige G3 is handy, the Yikes G4 is handy, lets give it a try. Did it and the Beige “G4” booted up. System profiler recognizes that there’s now a G4 processor in it. Unfortunately the G4 ZIF has to go back to the Yikes.

 

 

G4 ZIF in a beige G3 works. You may have to change de CPU Ratio due tu bus speed difference but it works. PowerLogic and others used to make G4 ZIF upgrades for Beiges.

Got a PowerLogic G4 on my G3 MT. Stock regulator board IIRC

 

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Just an update here. I haven’t looked at the voltage regulator yet but I did decide to buy a working PowerMac G3 motherboard off eBay for $50 free shipping to use for diagnosing the CPUs I have. 
 

It looks like you can use a standard PC ATX power supply with the G3 motherboards by moving a jumper on the board. I plan to build this info a standard PC ATX minitower case. 
 

Any caveats I should be aware of?

 

The board I bought looks like the 233mhz version and I can’t tell what voltage regulator it comes with at the moment. After I’ll have a G3 inside a nice PC tower. Frankenstein, yes, but not crumbling and falling apart like the beige Macs do. 

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@MrFahrenheit  You're probably already aware, but the bus speed and CPU speed multiplier (X bus speed gives CPU  speed) are controlled by the jumper bank on the logic board.   If the board was originally a 233, then it's probably set to a 66MHz bus speed with a 3.5X multiplier.

 

For initial testing, I would leave the jumper block at the original settings (assuming it is still in original configuration).   That will give you functional testing of ZIFs at conditions that are not challenging.  None were shipped rated for less than 233 MHz speed.

 

Then you can alter the jumper settings later for each module, if you want to test their limits.

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On 2/23/2021 at 8:05 AM, trag said:

@MrFahrenheit  You're probably already aware, but the bus speed and CPU speed multiplier (X bus speed gives CPU  speed) are controlled by the jumper bank on the logic board.   If the board was originally a 233, then it's probably set to a 66MHz bus speed with a 3.5X multiplier.

 

For initial testing, I would leave the jumper block at the original settings (assuming it is still in original configuration).   That will give you functional testing of ZIFs at conditions that are not challenging.  None were shipped rated for less than 233 MHz speed.

 

Then you can alter the jumper settings later for each module, if you want to test their limits.


I did know about the jumper block but I wasn’t aware I could just run them all at the lower speed for initial testing. This is great news. Thanks!
 

I still haven’t received the board yet (weekly trips to post office due to covid). 
 

From the photos the voltage regulator is the good one. I went and looked and the voltage regulator in my beige g3 is also the good one. 
 

Some of the CPUs I have are G4 350/400/450 MHz. Will these also work no problem in the G3 beige motherboard?

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On 2/23/2021 at 12:27 PM, MrFahrenheit said:

Some of the CPUs I have are G4 350/400/450 MHz. Will these also work no problem in the G3 beige motherboard?

 

I think that's right, but I'm not certain.  I don't remember there being an incompatibility...   This is where I wish the old resources at xlr8yourmac.com were still up.  He had a great user contributed compatibility database.   And some of the best, most technical discussion in the long gone forums....

 

Some of the old articles are still there, so you might look for anything with G4 CPU in Beige G3.

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