G4 Cube CPU Upgrade

[broots]

Hi, I am looking to upgrade the stock 450MHz CPU in my G4 Cube and just acquired two G4 towers (Sawtooth and Quicksilver) with Sonnet cards. One is the Sonnet Encore/ST 1.4GHz (SG4-1400-2M) and the other the Sonnet/ST Duet Dual 1.8GHz (SG4D-1800). Neither are specifically designed for the G4 Cube so I understand there are concerns with heat and overtaxing the VRM. Does anyone have experience or advice with these upgrades in a cube? Can I use either with the existing Cube heatsink? I will be adding a fan. Does the VRM need to be upgraded too? These parts are so hard to find! Any advice will be appreciated!

Thanks!

 

[eyoungren]

The Duet 1.8 you have won't fit in the Cube. There was version of the same CPU that was released for the Cube and it's got a lower profile.

However, in my searching for my own 1.8 Duet I ran across forum threads (in other forums) where a Cube was modified somehow to make the standard Duet fit. I have no idea though what those modifications were.

You have gold there though with that Duet. If it's functioning, you can get $250-300 for it alone. I'm not telling you to sell it, just telling you how valuable that CPU is. It's one of the few Holy Grails of the PowerPC world.

 

[broots]

The Duet 1.8 you have won't fit in the Cube. There was version of the same CPU that was released for the Cube and it's got a lower profile.

However, in my searching for my own 1.8 Duet I ran across forum threads (in other forums) where a Cube was modified somehow to make the standard Duet fit. I have no idea though what those modifications were.

Yes, I see what you mean. The 1.8 Duet looks like it runs into the IDE connector on the motherboard.

 

[eyoungren]

Yes, I see what you mean. The 1.8 Duet looks like it runs into the IDE connector on the motherboard.

I should be clear that when I was looking for a 1.8, it wasn't the version for the Cube as I do not own a Cube. Hopefully though, someone here might be able to detail the modifications necessary to make your's fit.

 

[ervus]

Nice find, those are definitely some rare components. Was this where you got them?:

www.ebay.com/itm/333664666763

Either of those CPUs could be used in a Cube, but as you already know power/heat is the main problem. Sonnet CPUs are not configurable without a soldering iron, so you can't easily adjust speed or voltage settings. Both of those CPUs would need a VRM upgrade. The 1.4 single *might* be ok with just some heatsinks added to the Apple VRM, but it's risky and potentially expensive. The 1.4 can work with the oem Cube copper heat spreader, but the dual 1.8 will need some customization. You can basically hold it up to the Cube heatsink and see what needs to happen for it to fit. I've seen it done but it would not be as easy as the 1.4 CPU.

Good luck with your projects and let us know how it goes!

 

[broots]

Nice find, those are definitely some rare components. Was this where you got them?:

www.ebay.com/itm/333664666763

Hi Ervus! Yes, that was the auction. The original owner didn't want to part it out so I am the proud new owner of the whole collection in a small NYC apartment.

Thank you for the tips! I am considering the Stratos VRM from this site (translated), though I wonder if the seller is truly still active? Either way I will add copper heatsinks to the original VRM mosfets.

Is there any good way to test or monitor the original VRM to responsibly use it with the Sonnet 1.4? I did read about Wouter3's journey in the forums here with burning out a VRM module and would like to avoid that.

 

[ervus]

If you want to try the 1.4, I would suggest testing it with thermocouples on the CPU and VRM to monitor temperatures. I don't think I've seen anyone post results of this sort of testing and it would be interesting to see. You can get inexpensive thermocouple equipment that would take some of the guesswork out of experimentation. You could put thermocouples on the stock Cube to get a baseline, and if you can maintain these temperatures or even get them lower based on your fan/heatsink setup I think you could avoid an expensive meltdown. Knowing the temperatures could also help you tune the fan/heatsink setup to know if lowering the fan speed/noise is starting to compromise temperature.

Also, do you have a volt meter? If you can measure the voltage on the CPU I can give you an estimate of its power draw. If it's at a low enough voltage, the power draw would be similar to a dual 500MHz CPU, which has been done in a Cube often enough with the stock VRM.

With OS X and CHUD utils you can install a CPU preference pane that lets you enable nap mode on the CPU. This significantly drops the power/temperature at idle, and if you use a temperature controlled fan the Cube can be essentially silent at idle.

 

[broots]

Good ideas! Testing with thermocouples sounds perfect. I will make some time for this next month and report back.

Yes, I have a digital multimeter. Where is the pin to measure CPU voltage?

 

[ervus]

There are a variety of points you could measure the voltage. One of the easiest that I can see from your picture is the large pad on the inductor under the "A" in the A1094 sticker. The Cube heat plate has a cutout for the inductor, so you could put the heat plate on the CPU and plug the CPU into the Dgital Audio and start it up with the case open. You can probe that pad to get the voltage and then shut down the machine before the heat plate gets too hot.

 

[PJMacMan]

Hi, I am looking to upgrade the stock 450MHz CPU in my G4 Cube and just acquired two G4 towers (Sawtooth and Quicksilver) with Sonnet cards. One is the Sonnet Encore/ST 1.4GHz (SG4-1400-2M) and the other the Sonnet/ST Duet Dual 1.8GHz (SG4D-1800). Neither are specifically designed for the G4 Cube so I understand there are concerns with heat and overtaxing the VRM. Does anyone have experience or advice with these upgrades in a cube? Can I use either with the existing Cube heatsink? I will be adding a fan. Does the VRM need to be upgraded too? These parts are so hard to find! Any advice will be appreciated!

Thanks!
View attachment 937965 View attachment 937966

Good luck with retrofitting looks entertaining , Id be interested in the unit you don't plan on using though...

 

[ervus]

I've been looking for a Cube CPU too, but they seem really rare. I saw this:

www.ebay.com/itm/143667173708

I would guess that's a 800MHz Powerlogix CPU, but that listing looks like a real gamble.

 

[cosmichobo]

G'day,

I have a Cube which I picked up 5 years ago off eBay. It has a Sonnet 1.5Ghz card. That's about all I know about it.

Do the Sonnet cards usually allow you to boot into OS 9?

I've been trying to start my Cube up from 9.0... then 9.1... and now 9.2... but it just gives me a grey screen. Nothing else.

The Sonnet card is the one major variable...

Is there some kind of driver or other software solution to make OS 9 work?

Thanks