G5 Quad - 32GB possible?

[666sheep]

THX for the link zen A lot of reading ahead me

Has to be. A 32bit Kernel would limit the RAM to 4GB, yet the PowerMac G5 is advertised to work with up to 16GB of RAM (which it does).

I don't know of any other technology that would make a 32bit Kernel address more than 4GB.

This seems to be a little too complex for my mid-techy mind, but I think that's a benefit of 64-bit CPU and 42-bit MMU. In contrary to 36-bit PAE MMU which x86 uses. There's an interesting comparison of CPUs/Memory bus features (esp. second table):

http://www.appleinsider.com/articles/08/08/26/road_to_mac_os_x_10_6_snow_leopard_64_bits.html

So, if I understood it right way, Intel 10.5 kernel uses PAE instructions and PPC 10.5 kernel uses 42-bit MMU features instead of PAE?

Please, be lenient for me, I'm not educated in computer science All I know about Macs came from years of real life experiences with Mac (more) and PC (less) hardware, so I have lack of theoretic basis here and there.

 

[MacSince1990]

There have really only been a handful of macs that can go beyond their max. RAM spec.

Actually historically most did. It's true for the Power Mac 8x00's, 9x00's, Beige G3s, etc, and most Macs before it.

I will never understand in a million years why Apple allowed a 2GB limit in the first 2 G4 towers with AGP and then limited the next 2 models to 1.5GB

It had to do with logic board design and space requirements. It just has one fewer RAM slot.

These days, I can't imagine living without my 6.2GB ram disk.

An SSD would probably be faster.

The original PM 6100 released in 1994 was 64 bit too, it only supported 72MB.

No... it wasn't. It was 32-bit, just like every other Apple-used PowerPC processor for the next 9 years. The FPU was 64-bit, the memory and bus were 64-bits wide... but the CPU/ALUs were certainly 32-bit.

And it's actually expandable to 136 MB. It has two slots, each can accept up to 64 MB, but that's a limitation of the memory controller, among other things.

Anyway, did anyone find out if the G5 can support up to 32 GB?

 

[mac.tastic]

An SSD would probably be faster.

RAM is always faster than any drive interface.

In the case of the G5's very limited SATA-I, the RAM is vastly faster in every way.

 

[MacSince1990]

RAM is always faster than any drive interface.

In the case of the G5's very limited SATA-I, the RAM is vastly faster in every way.

Actually not really, due to how RAM disks are actually managed.. you don't get the full speed of your memory. Plus I assume he uses a Mac Pro, although I could be wrong. The fastest SSDs can go above 1 GBps.

 

[mac.tastic]

*Blah blah, something MacSince1990 knows nothing about*

I just proved RAM is faster than an SSD by a factor of 4. No SSD on the planet can sustain 81.5MB/sec of random 4k writes except the extremely parallel and extremely expensive 1TB+ PCIe cards.

Plus I assume he uses a Mac Pro, although I could be wrong. The fastest SSDs can go above 1 GBps.

That would explain why hes posting in the PowerPC section in a thread asking about G5 ram.

 

[AdrianK]

That would explain why hes posting in the PowerPC section in a thread asking about G5 ram.

MS1990 was quoting 300D, who is not the OP of this thread and has not suggested in this thread (that I can find anyway) that he/she uses a PMG5.

 

[burnout8488]

So,

Did that OWC guy ever load up a PowerMac with 32Gb?

 

[zen.state]

So,

Did that OWC guy ever load up a PowerMac with 32Gb?

If you look at the original post the OP has been banned. They can't answer.

I can't imagine this working anyway. Most memory limitations in Macs are hardware limited so there is no way around it. Especially with PowerPC Macs.

 

[burnout8488]

If you look at the original post the OP has been banned. They can't answer.

I can't imagine this working anyway. Most memory limitations in Macs are hardware limited so there is no way around it. Especially with PowerPC Macs.

Damnit, I missed that. That makes sense though. More of a "I wonder if it can be done" thing with no real need or reason.

 

[Cox Orange]

Apple.com, LowEndMac, and Wikipedia(yes i know but hey i find it 50% reliable half the time lol) says 16gb so i guess 16gb only

btw why hasnt the above comments answer the OP's question??? or am i missing something here?

http://www.apple.com/pr/library/2005/oct/19pmg5.html

everymac.com says 16GB, too and they usually write down every little info that goes beyond what apple says (i.e. that you can use a second monitor on an ibook by installing a hack or that the iMac G3 does support 1GB though 512MB officially stated...), but they could have missed it, since their info comes from user experience and what OWC finds out.
(another place to look for info would be apple-history.com)

sorry for coming up with a not so tech-y add

 

[Iroquois]

I can't imagine this working anyway. Most memory limitations in Macs are hardware limited so there is no way around it.

Flip the ol' thinking cap switch on for a second.

Support for 4GB ram sticks x 8slots = 32GB. Huh, imagine that. Pretty simple. I don't see why there is need for further discussion beyond post #2.

 

[zen.state]

Flip the ol' thinking cap switch on for a second.

Support for 4GB ram sticks x 8slots = 32GB. Huh, imagine that. Pretty simple. I don't see why there is need for further discussion beyond post #2.

Lots of computers can take certain larger sizes of RAM in 1 slot but that still doesn't increase the system max.

If you want to spend whatever 32GB RAM would cost based on a delusional assumption be my guest. Delusion is not reality.. reality is reality.

 

[Iroquois]

Delusion is not reality.. reality is reality.

Oh my. Looks like we have a non-believer!

 

[zen.state]

Now lets see the activity monitor memory info where it shows in the numbers that only 16GB is recognized. A couple system profiler screen snaps proves nothing about how much the system sees and uses.

My Mac mini in my home theatre setup is a C2D and has a 3GB max. Even though I have 2x 2GB DIMM's in it and it shows 4GB in about this mac and system profiler the numbers in iStat menus and activity monitor only total 3GB.

Do you actually think some random screen snap of system profiler proves your point? System Profiler will show whats there regardless of any limitations.

 

[mac.tastic]

System Profiler will show whats there regardless of any limitations.

The original question was "would the machine go beyond 16GB like the 2006 mac pros after it? Remember the 2006 mac pros had a max of 16GB of memory according to Apple. But, OWC saw it could take up to 32GB?"
Given that its been proven the system supports 4GB modules, the question if they worked or not was never asked! So in the end, your trolling has meant nothing.

 

[burnout8488]

Now lets see the activity monitor memory info where it shows in the numbers that only 16GB is recognized. A couple system profiler screen snaps proves nothing about how much the system sees and uses.

I would be very interested in seeing this screenshot as well. That's what matters.

Given that its been proven the system supports 4GB modules, the question if they worked or not was never asked!

Isn't that assumed though? Who would care if it wasn't actually usable?

 

[zen.state]

He and others just don't get it. Luckily for me I added mac.tastic to my block list so I don't have to read his delusions any longer. Or trivial use of words like rape to describe HD performance.

 

[chrismacguy]

The original question was "would the machine go beyond 16GB like the 2006 mac pros after it? Remember the 2006 mac pros had a max of 16GB of memory according to Apple. But, OWC saw it could take up to 32GB?"
Given that its been proven the system supports 4GB modules, the question if they worked or not was never asked! So in the end, your trolling has meant nothing.

Hooray, so the system knows it has 32GB RAM installed. Whoop-de-doop. Not much use if the system only lets you use 16GB of it is it? If the system cant use the extra RAM, having it has no use, which was what *should* have been being asked, now Iroquois - do us all a favour and take the screenshot in Activity Monitor, so this thread can go away, as if the G5 Quad can take 32GB, I might buy one (to replace the raft of G4s I currently have for PPC Software), if it can't use all 32GB, let us know so we can get on with our day and know for a fact its been tried and it works (System boots), but is useless (System wont let us use it).

 

[mac.tastic]

Hooray, so the system knows it has 32GB RAM installed. Whoop-de-doop. Not much use if the system only lets you use 16GB of it is it?

Whats the difference as compared to an Intel machine that doesn't use more than 3GB out of 4?

Who cares if it actually uses 32GB? If you need that much memory then its very likely a G5 is far too weak for what you're working with and you'd be far better served by a MacPro. I'm happy 4GB modules work, that means when they get cheap I can ditch my two 512mb modules and get from 9GB to 16 without wasting any 1 or 2 GB modules.

zen.state, I'm happy you're ignoring me. That way your extremely poor education won't get in my way.

 

[chrismacguy]

Who cares if it actually uses 32GB? .

Let's see now... errr Me? Since I currently have a 16GB equipped G5 Dual 2.7 in use as a Imaging station at one of my clients, and the software isnt that CPU dependant, but its for scientific imaging, so it uses RAM like no tomorrow. So if I can bump that system up to 32GB and extend its life by another 5 years, its easier to do that than make them buy a new Intel Mac Pro and new licenses for all their very expensive software.

 

[mac.tastic]

The 2.7 and Quad are completely different machines.

and new licenses for all their very expensive software.

Install them on the new machine. As long as they are removed from the old machine there is no legal or logical reason they can't be reused. If they're PPC code, stick to SL, the MP is plenty powerful to convert the code in rosetta if its not very CPU dependent as you say.

 

[chrismacguy]

The 2.7 and Quad are completely different machines.


Install them on the new machine. As long as they are removed from the old machine there is no legal or logical reason they can't be reused. If they're PPC code, stick to SL, the MP is plenty powerful to convert the code in rosetta if its not very CPU dependent as you say.

(0) I am not a Mac Noob. I know they are different machines, however if this works I was talking about buying a used Quad to replace the Dual 2.7. In fact judging by your posts I likely know more about the guts of Macs than you do.
(1) A G5 Quad costs a lot less than a new Mac Pro, the software is nearly $30,000/seat
(2) The software doesnt run under Rosetta, it requires a G5 chip. Its portable, but only between G5s. Rosetta only provides G4 emulation so thats not an option. Its not CPU Dependant in that it doesnt use much CPU performance, It does however use a lot of G5 in-flight instructions from what I recall with the conversations Ive had with the developers, who only released an Intel Version 6 Months ago. (And even then it doesnt have all the imaging features of the prior edition my client uses).

 

[mac.tastic]

In fact judging by

Don't quit your day job noobie. I've owned and serviced Macs since 1988.

 

[AdrianK]

Who cares if it actually uses 32GB?

The people that want 32GB of RAM in their G5s? Is this a trick question?

Whats the difference as compared to an Intel machine that doesn't use more than 3GB out of 4?

How is that relevant in the slightest? I have a feeling that owners of intel machines would be pretty interested to know whether 4GB will be utilised in their machines, rather than just 3...

 

[zen.state]

I'm thinking the people who paid for 32GB and only get to use 16GB wouldn't be too happy. They just might care.

If someone wants to burn money on 16GB worth of RAM they can't use why not just donate the money to some charity?

Is it just me or is this really getting on the cusp of complete insanity?