Interest in adapting 744x to 7400?

[herd]

I've been playing some more and I think the dual 7447 would be safe on the stock Cube VRM at 1GHz. At this setting it uses less peak power than a dual 500MHz 7400 from a Gigabit Ethernet tower, and these CPUs have long been a popular upgrade for the Cube (using the stock VRM).

The version of CHUD that I have won't enable NAP mode on dual CPUs for some reason, so in this situation the CPUs always need fan cooling. However, CPU Director will enable both NAP and DFS which cuts the idle power to almost nothing. With DFS enabled, even under full load the dual 1GHz 7447 (at 500MHz w/DFS) uses less power than the stock 450MHz CPU. I think I'll call the experiment complete.

 

[joevt]

The version of CHUD that I have won't enable NAP mode on dual CPUs for some reason, so in this situation the CPUs always need fan cooling. However, CPU Director will enable both NAP and DFS which cuts the idle power to almost nothing. With DFS enabled, even under full load the dual 1GHz 7447 (at 500MHz w/DFS) uses less power than the stock 450MHz CPU. I think I'll call the experiment complete.

What version of Mac OS X are you running? I think CPU Director doesn't work on anything later than Mac OS X 10.4.9 but at least CHUD can be used to verify the CPU settings.

 

[Quadraman]

Would this mod cause heat issues on the confines of a G4 Cube?

 

[Mikeyy00]

Hey Herd.. is that something I can pay you for (a 1ghz+ upgrade for the Cube?.. ) Currently waiting on my Artmix VRM to get fixed so I can use a Sonnet 1ghz without letting out the smoke.

I have a few spare stock 450 CPU cards that could be used as a donor card.. I could even send you the Sonnet to put towards payment or something.. ?

 

[Mikeyy00]

Hey Herd.. is that something I can pay you for (a 1ghz+ upgrade for the Cube?.. ) Currently waiting on my Artmix VRM to get fixed so I can use a Sonnet 1ghz without letting out the smoke.

I have a few spare stock 450 CPU cards that could be used as a donor card.. I could even send you the Sonnet to put towards payment or something.. ?

@herd

 

[indibil]

I guess I never followed up on this thread. In case any Cube enthusiasts care, the chip swaps I mentioned work fine. A 7447 at 1.2GHz uses roughly the same peak power as the stock Cube CPU. I think 1.4GHz is still conservative enough to use the stock VRM, but fan(s) should be added. Anyway, FYI.

The Dual CPU swaps also work. I've been running this in my Cube for a while at dual 1.2GHz.

View attachment 62130

I looked at these two photos and I have two questions. Are the additional interposer capacitors optional? in the dual they are not placed.

My other question is that the 7400/7410 have PLL0-3 but the 7447 has PLL0-4, where do you adjust the additional PLL4 when you use interposer? I only see pads for capacitors, not for resistors.

Thanks for your contribution!

 

[CD5150]

Hey. I was wondering if these G4 CPUs could be transplanted on to a processor card from a Beige/Blue and White G3. It would be cool to lift a G3 off the Processor Module just to put a G4 on it.

 

[Phipli]

Hey. I was wondering if these G4 CPUs could be transplanted on to a processor card from a Beige/Blue and White G3. It would be cool to lift a G3 off the Processor Module just to put a G4 on it.

If you use a 7400 or 7410 rather than what is discussed here, you don't need anything extra, but need to set core voltage and check cache voltage compatibility. The 7410 dropped compatibility with the cache voltage that was commonly used with G3s. Simple solution is taking a G4 and cache from a more modern G4 processor card that suits.

You'll still need to make sure vcore is set correctly. Also the cache voltage if you're using lower voltage cache with a 7410.

 

[herd]

I have not yet tried to install a 7447 into a G3 machine, but in theory it should be possible. The Pismo may be my first attempt. There is some preliminary discussion of that in this thread:

68kmla.org/bb/index.php?threads/550mhz-g4-powerbook-pismo-vs-titanium.45851/

As others have mentioned, there are a few things to consider besides the pin-out of the chip when swapping CPUs. For example, most of the different firmware versions for these computers that I've worked with are set up specifically to block CPU upgrades. I think fixing this would one of the first steps.

 

[Phipli]

For example, most of the different firmware versions for these computers that I've worked with are set up specifically to block CPU upgrades. I think fixing this would one of the first steps.

I think I remember the B&W G3 was the first to do this, and you should be OK with a beige G3.

 

[indibil]

I have not yet tried to install a 7447 into a G3 machine, but in theory it should be possible. The Pismo may be my first attempt. There is some preliminary discussion of that in this thread:

68kmla.org/bb/index.php?threads/550mhz-g4-powerbook-pismo-vs-titanium.45851/

As others have mentioned, there are a few things to consider besides the pin-out of the chip when swapping CPUs. For example, most of the different firmware versions for these computers that I've worked with are set up specifically to block CPU upgrades. I think fixing this would one of the first steps.

I will soon have a G3 B&W tower and I have an extra G3 233MHz ZIF CPU. If you want we can try updating to 7447, I have a 1.25GHz taken from a Mini. As the B&W supports bus overclocking to 133MHz, with the X8 multiplier it could reach 1067MHz, I don't know if the interposer allows PLL4 to be adjusted to reach higher speeds.

I will only need to locate where the Vcore is set on the motherboard to act on it, at least on the last diode before the CPU.

We tested it? The Sonnet patcher literally says "Version 3.1 adds support for Power Macintosh G3 (Blue & White) and all Power Mac G4 computers."

I also have a Lombard but I don't have an extra CPU to test.

 

[herd]

Someone sent me some 7448 chips to install, and I can report that they also work fine on these boards with the 7400 adapters. The Powerlogix/Newer Technology patch works to fix the firmware on machines that use these boards.

 

[indibil]

Someone sent me some 7448 chips to install, and I can report that they also work fine on these boards with the 7400 adapters. The Powerlogix/Newer Technology patch works to fix the firmware on machines that use these boards.

Great!!!

Some pics?

 

[herd]

The extra cache seems to have a bigger benefit on the slower bus in the Cube:

 

[indibil]

The extra cache seems to have a bigger benefit on the slower bus in the Cube:

It is a good result, similar to the Mac Mini G4 7447 @1.92GHz and with a bus of only 100MHz.


If I ever get a pair of 7448s my intention is to try a dual QS processor that I have, which has a failing L3 cache. With interposers and a 133MHz bus it can give a good result.

Did you try it?