Dead GE tower vs. AGP

[James Gryphon]

I have a Gigabit Ethernet G4 tower that appears to be completely dead. It doesn't boot at all, and pressing the PMU switch for half a second or so didn't change anything, nor did removing the battery. I'm inclined to think the power supply's out of order.

I already have another G4 tower which does work, an AGP, and I only 'need' one*. At this point I'm wondering if the mild advantages of the G.E. that I've seen listed (far faster Ethernet, slightly faster cache bus, and of course the dual processor) over a Sawtooth justify the trouble and possible expense of figuring out the power problem. If the Sawtooth has any pros of its own at all, I'm not sure I wouldn't be inclined to keep it and sell the other.

(My first inclination is always to keep a spare of everything, but then you'd want spares for the spares, so... we need to clean the house out, and it seems the only way to get forward is to take a decisive stand and move out the things we're not going to make optimal use of to people who will appreciate it more.)

 

[Raging Dufus]

The advantages the G.E. has over the Sawtooth can be overcome in certain circumstances.

I'm not familiar with the "slightly faster cache bus" though, first time I've heard that - but if it's because the G.E. CPU's are generally faster than the Sawtooth's, you should know that G.E. CPU's will perform at the same speed in a Sawtooth. So a G.E. CPU's cache bus should perform equally well in a Sawtooth.

If your G.E. has dual CPU's, the later revisions of the Sawtooth can also handle dual CPU's. You can check your Sawtooth's compatibility by using this tool:

Newer Technology® : AGP Dual Compatibility

Newer Technology determine dual processor compatibility with Power Mac G4 Gigabit Ethernet.

www.newertech.com

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Finally, the Sawtooth's slower ethernet can be overcome by means of a Gigabit NIC installed in one of its PCI slots. You can read more about that here:

PCI Gigabit Ethernet on the cheap

Liberating the greatest computer architecture ever created.

powerpcliberation.blogspot.com

I've used one of the TrendNet cards he recommends there, it's plug & play and works like a charm.

Sounds like you're right about the dead PSU in your GigE. There's something you can do about that too, if you want to keep using it. Used PSU's for the GigE and Digital Audio (interchangeable w/GigE's PSU) can be found on eBay, and you can also roll-your-own adapter to make a PC ATX power supply work:

http://atxg4.com/gige-da.html​

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There's lots to explore there, whatever way you go. Have fun!

 

[DearthnVader]

Other than the faster ethernet, doesn't the Gig-E also have ADC?

You'll lose the ADC if you go with a PC power supply, or you swap a Sawtooth logic board.

If you use a flashed PC video card, the sawtooth is the better logicboard for AGP cards that support 8x AGP.

Apple used some reserved pins for the USB lines of the ADC, later 8x AGP used the pins in a way that forces you to disable them on ADC logicboards that don't support 8x AGP( G5's with ADC ).

Pins 3 and 11.

 

[Raging Dufus]

Other than the faster ethernet, doesn't the Gig-E also have ADC?

You'll lose the ADC if you go with a PC power supply, or you swap a Sawtooth logic board.

If you use a flashed PC video card, the sawtooth is the better logicboard for AGP cards that support 8x AGP.

Apple used some reserved pins for the USB lines of the ADC, later 8x AGP used the pins in a way that forces you to disable them on ADC logicboards that don't support 8x AGP( G5's with ADC ).

Pins 3 and 11.

Yes, that's true. Sometimes I forget about ADC because I've never used it.

I can only think of one 8x AGP card, though, that will work in a Sawtooth/GigE's 2x slot: the Radeon 9800 Pro. Better get off your wallet for that one.

 

[ervus]

The dual CPU is a definite advantage in Mac OSX. You could swap the power supply, but it would probably be easier to swap the dual CPU to the working machine.

 

[DearthnVader]

I can only think of one 8x AGP card, though, that will work in a Sawtooth/GigE's 2x slot: the Radeon 9800 Pro. Better get off your wallet for that one.

The GF 5200/6200 were x8 AGP.

I modified many GF 6200's to work in the 2x AGP Cube.

Just to complete the thought on ADC, the power supply must have 28v@around 3 amps for the 75w output. That's why PC power supplies can't drive it without a step up board.

Back in the day I tried to find a 28v supply, only thing I could find was US military two way radios had 28v. So the military vehicle like the HUMVEE had 28v charging ports. The 28v board for them I could find was around $300 and I think it was 4a.

However, likely the HUMVEE had two 12v batteries connected for 24v electrical systems.

Just something I looked into long ago.

 

[Raging Dufus]

The GF 5200/6200 were x8 AGP.

I modified many GF 6200's to work in the 2x AGP Cube.

Just to complete the thought on ADC, the power supply must have 28v@around 3 amps for the 75w output. That's why PC power supplies can't drive it without a step up board.

Back in the day I tried to find a 28v supply, only thing I could find was US military two way radios had 28v. So the military vehicle like the HUMVEE had 28v charging ports. The 28v board for them I could find was around $300 and I think it was 4a.

However, likely the HUMVEE had two 12v batteries connected for 24v electrical systems.

Just something I looked into long ago.

Interestingly off-topic

 

[bunnspecial]

The GigE is more or less a SMALL evolution of the Sawtooth. Aside from on-board GigE(which is easy to add to a Sawtooth if you're so inclined with a separate NIC), the other major difference is that it supports ADC. Also, all GigEs will support dual processors, while only later Sawtooth boards will work with them. Oh, it also eliminates the mostly useless(IMO) 3rd Firewire port that's at the top of the Sawtooth LoBo.

Both run with a 100mhz FSB, and use PC-100 RAM at 100mhz. Both run their PCI slots at 33mhz, and the AGP slot is 2x. In that sense, they are effectively interchangeable.

TBH, I would let my desire to use ADC displays steer me toward one over the other. I use ADC heavily, and like computers that support it(although lack isn't a deal killer-I just have a bunch and it's fewer cables and plugs to deal with to get good quality displays).

If you have no desire for ADC support, bear in mind that PSUs for all of these are getting up in years. Standard ATX PSUs are not directly PNP in a Sawtooth, but require minimal modification to work. An ATX PSU can be made to work in a GigE, but you need to modify them more and will lose ADC.