This page is a wiki. Please login or create an account to begin editing.


42 posts / 0 new
Last post
3371-Alpha's picture
Offline
Joined: 2016 Mar 15
G5 Quad/Late 2005 Myths

These are thing that have been driving me crazy for a while! There are three myths about the quad/pcie enabled late 2005 G5 Mac that I really want resolved. First is the RAM; according to IBM specs the G5's U4 can support 64GB of RAM. Of course 32 bit OSes (which is actually every Mac OS before Snow Leopard, prior OSes only had 64 bit extensions) can only see up to 32 GB max. Be that's the thing, someone has claimed to have achieved that. You can't believe everything you see on the internet of course, but what if?

The second one's not as big but still cool. In this thread, a guy says you can actually upgrade the internal wifi/bluetooth combo chip to be wireless N compatible. He didn't specify any serial for the chip or anything like that, but that the chip will require it's own antennas as the builtin ones don't fit on the card. Any info on this card wold be appreciated.

Last one is, as you may have guessed, dealing with the graphics. We already know that you can install a faster PC graphics card in the quad if you have the right ROMs, in fact I'm the one who uploaded them to this site. But I've also read those 7800 GTX ROMs also work on some models of the 7900GTX (the ones based on the 7800GTX reference card). I've also heard you can overclock the card, but I've found no info on either of these beyond gossip.

Apple defiantly left a lot of things unused when they moved to intel. I just want theses myths resolved so I can sleep tonight and stop wondering about them. Any help/advice appreciated.

Comments

SkyCapt's picture
Offline
Joined: 2017 Jan 11

There are mistakes in your RAM description. Whether the OS software is said to be 32-bit or 64-bit does not affect maximum RAM capacity, per se. What matters is whether the CPU math units are 32-bits per cycle, or higher such as 64-bits per cycle. 32-bits unfortunately does not equal 32GB, the limit of the 32-bit CPU is actually 2GB. PowerMac G5 was the 1st 64-bit CPU and therefore the 1st Mac to allow more than 2GB RAM. This is true, the 2GB max of PowerMac G4 is that particular tech at the end of its rope, and more RAM was a major impetus for making the 1st 64-bit CPU at that time. I have a PowerMac G4 (manufactured parallel to G5) and I can stuff 4GB into it, AHT v2.0.2 and AHT v2.1 both do recognized all 4GB, but OSX all PPC OSX ignore the 4GB and say there is only 2GB, OSX all versions do this because they observe the CPU G4 is 32bit.

I don't know about GT cards nor wireless, but I'm into memory. The 32-bit unsigned RAM limit is technically 4GB but Apple like many go with the signed number limit which is 2GB. With signed math and 2GB, it means any 32-bit number can describe the Distance from one memory cell to another, such as the distance from the last cell to the first (minus 31bits) and from the first to the last (positive 31bits). The 32nd bit is reserved for telling whether the other 31bits are positive or negative. Keeping signed math, more than 2GB needs more than a 32-bit number and therefore more than a 32-bit CPU. The 32-bit CPU can be made to handle memory more than 2GB but has to chain 2 instructions together for every memory operation that used to be 1 instruction, it can be done, noticeably slower, but wasn't done.

2 (binary) to the 32 power = 4GB.
2 (binary) to the 31 power = 2GB. This is why Macs with 32bit CPUs have always 2GB or less.

Physically, RAM limit in most models is set by the number of wires implemented in the RAM slots and the uni-n chip (your U4), the CPU itself often capable of more ram, but Apple and most mobo makers wouldn't give you more expansion than was reasonable at the time. Imagine an anti-virus/malware/security app which must constantly scan all of RAM. Installing 10X more ram than you need must slow it down by almost 10X.

It wouldn't surprise me if some Quads have a 32GB limit while others can be pushed to 64GB. There are several other Apple models documented as accepting more ram than declared. But what will you do with all that ram? 2GB is fastest, to this day. I've got an Intel-Mac with a U4 (uni-n v4 "Kodiak" 2nd or 3rd revision) controller, and I can measure it speeding up when I reduce RAM from 3 or 4 GB down to 2GB (meaning 2x1GB pair of modules, 1x2GB would also be slow for lack of parallelism). There is still software all over the place which operates >2GB by way of chaining 2 instructions together for Every RAM computation. I deliberately keep 2GB in this DDR2 Mac o'mine to keep it the fastest, along with other tricks like RAM overclocking, and RAM tax relief.

3371-Alpha's picture
Offline
Joined: 2016 Mar 15

In fairness, RAM is partly software based actually. You see, if a machine is not programed to use something, then it won't. This is true for memory. 32-bit OS can't see more than 4GB of unsigned or 2GB of signed memory, but some OSes (particularly UNIX based ones) have an extender. It allows it to address more than the 32-bit limit but also requires the hardware to support it too. I remember reading that darwin's extender caps out a 32GB. The true 64-bit versions don't have this issue though.

Knez's picture
Offline
Admin
Joined: 2010 Feb 11

I don't see any reason why it shouldn't be able to make use of 32gb RAM. Using PAE, each 32bit application is limited to 4gb of RAM, but this doesn't keep the system from having more.

If we take the G4 for instance; it's not capable to address more than 2GB of RAM. The CPU has to address the RAM in order to see it, so if you put more than 2GB of RAM in for instance a PowerMac G4 "MDD" it won't see more than 2GB because it can't address it. If it can't address it, it does not exist.

What PAE (Physical Address Extension) does is map the memory to "virtual" addresses which permits the use of more RAM than the hard limit of the CPU architecture permits.

So what I'm saying is that if the Quad can "see" 32GB of RAM, then it can address it. If it can address it, it can use it.

Both me and fogWraith have Quads, so just wait for a bit and we'll debunk all the myths Smile.
Let's get the RAM, run tests to fill all the 32GB's and we'll know for sure. Given my experience I'm almost certain that the Quad can make use of all the 32GB's.

SkyCapt's picture
Offline
Joined: 2017 Jan 11

If hypotheses will be tested, then I hope a few good macs will try my idea 2x1GB=2GB DDR2 preferably in the matching slots that are nearest to the CPU(s), then look for improved snappiness speed in the overall system including graphics animating. Don't rely on numbers in benchmark software. Use your senses.

dronecatcher's picture
Offline
Joined: 2016 Jul 4

I've often wondered can too much RAM slow a system down - what is the reasoning behind this?

3371-Alpha's picture
Offline
Joined: 2016 Mar 15

Thanks for offering. I'd test myself but sadly I'm broke. I know the Quad runs PC-4200 though I don't remember the hertz. As for the card, be careful when overclocking it, older cards are getting rarer with every day, and if you set the cycles too high.....well you know.

SkyCapt's picture
Offline
Joined: 2017 Jan 11

G4 CPU handles 64GB of RAM (36 address lines). A 32bit-clean implementation of the G4 handles 4GB RAM. Apple's particular implementation of the G4 stops at 2GB. My MDD2003 PowerMac can effortlessly use all 4GB, but there would be bugs in apps using signed math on address manipulations >2GB, though no software that I use would be affected. Anyway, I could have 2GB system RAM plus a 2GB RAMDISK and resulting in zero incompatabilities.

So the 2GB RAM limit of G4 is software oriented, moreso firmware dictated. It would have slowed down the computer to allow more than 2GB system RAM, so Apple avoided doing it - they waited for their G5 to tackle this.

As for the G5, once the self imposed 2GB limit was breached, the Next limit became astronomical. 4TB (4096GB) is what RAM the G5 CPU can utilize. So in actuality RAM limit of any G5 computer is determined by its motherboard, not the CPU. And software has little to do with it. Any limit less than 4096GB must be deliberately added thru programming, whereas the Natural tendency would be for the software to allow it All. Thus, the true small physical limits seem to be enforced by the number-of-wires implemented between RAM slots and RAM controllers.

G5 Quad computers use DDR2-4200 (533 Mhz) and Apple declares its limit to be 16GB (eight x 2GB modules). Simply test one matching pair of 4GB modules to see if they're recognized. If so then you probably can install 8x4GB. Next try 8GB DIMMs, if so then probably 8x8GB will also work. Most likely you will find a 4GB module isn't recognized in any slot, this means the trouble is not you have a computer limited to 16GB, but really means you just have individual slots limited to 2GB thanks to U4 design/implementation.

-----

Overclocking RAM is easier than y'all think. The industry has been labeling things wrong for decades. I find new RAMs (DDR2) dirt cheap, and the new ones are better than the old.

Original RAM was most often built on the very latest fab process at-that-time and pushed near the limit of its switching frequency. This means old RAM creates a lot of heat and has limited success overclocking. New RAM however could run over 2000 MHz and when setting it to run at 'only' 533 MHz it functions low-power cool and sweet, and raising it to say 666 MHz is no big deal. It might even increase speed all by itself!, but yer stinking Apple won't admit that. You need to test each module solo to ferret out which modules function faster than others. In the MDD, you also gotta test them each in the slot farthest from the CPU, to ferret out which modules are prone to crashing due to CAS Latency (CL2.5). What heat danger you do gotta watch out for when improving RAM speed is, the RAM Controller chip can increase its heat output and even overheat usually leading to an instant shutdown rather than damage but don't risk damage. On these models we're discussing, the RAM controller has its own chip, its own heatsink, and its own fan motor. On the MDD, this is the famous "side fan" which you must make sure is performing well, and, even make sure it is facing the correct direction!

bertyboy's picture
Offline
Joined: 2009 Jun 14

Here's one for you, to do with memory.

But first, a quick point about Java. 64-bit java, and how it automatically runs in a 32-bit mode if the heap size is 2GB or less, or 3GB or less on Solaris.

So do we think that the Mac OS can do something similar ?
Why do I think this ?
Because my dual G5s, one loaded with 8GB, another with 16GB (and the poor dual 2.5GHz with its leaky coolant with another 8GB), all show 8GB in "About This Mac", but they show 2GB in Activity Monitor after a restart. Only when their total memory usage jumps about 2GB does Activity Monitor "jump" to showing the correct memory total.

Of course the G5's in Mac were famous for having to switch endianness, but I suspect that you know about this.

SkyCapt's picture
Offline
Joined: 2017 Jan 11

I saw that movie, "Endian: a jones and the last crusade."

Those things you mention about some 64bit software, sounds like it defaults to starting up and using a 32bit mode when the need for 64bits hasn't happened yet. That, or maybe thrown in a little "bugs in apps that use >2GB" mentioned earlier. If no bugs involved, it's using an internal 32bit mode to start up for an optimization. I think it goes to show, having actual 2GB (or less) RAM really does speed up the computer on a fundamental level.

Myself, I have no use for >2GB RAM. Tiger is my favorite OSX, used on both my PPC and my intell Macs. Tiger's minimum RAM requirement is 256MB, while 2GB is eight (read almost 10 X) the minimum. I sometimes run on 1GB while doing serious work inside a machine, and never ran out. To just play abandonware games from the Macintosh Garden, 2GB is consistently more than enough. I supposed if I did more internet, internet-video, and multitasking I might feel a little bummed by 2GB but VM buffering will keep the computer running and not crashing, more than 2GB has to be so top tier that most people ought not consider it, at least not in the realm of what is now decades-old Macs.

themacmeister's picture
Offline
Joined: 2009 Oct 26

No such thing as 8GB DIMM?! in my entire life, I have only ever seen 2 x 4GB DIMMs (which were bought from eBay, and SPECIFICALLY for AMD only - although they worked fine thanks to a good BIOS in GA-EP45-DS3L mobo).

I'm sure they probably made a DDR2 8GB DIMM for servers (ECC), but I have never seen one, and I have gone through HUNDREDS of DDR2 DIMMs...

fogWraith's picture
Offline
Joined: 2009 Oct 23

I think I have a stack of 8GB DDR2 modules in the back of one of my closets, I haven't even considered testing them in either of my Quad machines... PC2-5300 fully buffered, does the G5 even take those?

24bit's picture
Offline
Joined: 2010 Nov 19

As for second, it may be worth looking at the Hackintosh solutions.
Much will depend on the OS used and the available kernel extensions.

For instance, I am using these mPCI-e cards with OSX:
https://www.amazon.com/s/ref=nb_sb_noss?url=search-alias%3Delectronics&f...
They are accepted as Airport Extreme out of the box.

There are working PCI WLAN solution for OSX too out there.
TP-Link springs to mind, given that the Quads have "ordinary" PCI slots.
A TL-WN851ND (PCI) is working fine with OSX X86/64, no idea how support will be with PPC though.

3371-Alpha's picture
Offline
Joined: 2016 Mar 15

An older version of those cards would likely be needed, doubt Leopard would support the AC frequency. Another question though is weather it truly acts like an Airport card. Airport, despite what PC haters say, is slightly different from normal WI-FI. It has proprietary extensions like interference robustness and support Apple's own implementation of uPNP.

3371-Alpha's picture
Offline
Joined: 2016 Mar 15

Any updates?! I'm very eager to hear what happened, I'm like a soon-to-be-father pacing outside the delivery room!

SkyCapt's picture
Offline
Joined: 2017 Jan 11

I hear apple is transitioning to pure 64bit architecture, and they will be disallowing all 32bit software on newer models. I'm surrounded by lemmings, and there is this cliff here ...

24bit's picture
Offline
Joined: 2010 Nov 19

@3371-Alpha: This is the info about the WiFi card I had pointed to:

WLAN
Again, the little thing is working OOB. Yes, the Apple branded cards may have some additional Apple-Voodoo with them, though sharing the chipset and presumably plopping off the same conveyor. Smile

@SkyCapt: i´m 100% with you. Tons of good stuff, including the Mac emulators, are going to have a hard time when 32bit apps will have been dropped with MacOS 10.14.
Actually, I was thinking not to upgrade my laptop to 10.13, as macOS undergoes changes I dislike.
Nobody stops us using the OSX flavours 10.4 to 10.8 or running a Windows rig for home banking and the like.
Can´t say I will be happy with W10, but I guess I´ll get used to it.
W10 (1703) is still running e.g. Adobe CS2 flawlessly and Sheepshaver got back support for optical drives under 64bit OS thanks to a kind soul patching the emulator. (64bit mode is already impossible for Sheepshaver with macOS Sierra - CD-ROM support is missing either)
Time to say good bye macOS, hello Windows 10!

os9er's picture
Offline
Joined: 2013 Nov 15

@SkyCapt, @24bit: I agree with both of you. Frankly, I think dropping support for 32-bit apps in macOS is the latest in a string of bad decisions by Apple; prior examples include the removal of internal DVD drives on Macs and the removal of the standard headphone jack on iPhones. And, like you say, apps such as Classic Mac emulators will be strongly impacted by this change; with these emulators in particular, there's no way that I know of to transition them to 64-bit-only platforms.

24bit's picture
Offline
Joined: 2010 Nov 19

To continue our off-topic:
I did upgrade a spare SSD with Sierra to High Sierra on my Hackbook.
The upside: APFS is super fast and a real space saver.
The downside: CS5.5 became less usable and wake from sleep is not working as it is.
Last not least, I can't reach my DSL/Router box´s web interface any more!

For a MacBook pro High Sierra will be a great improvement, if only because of the SSD optimised APFS. For us regular guys wanting to run old software, it looks more like a coffin nail. Wink

muttztfz's picture
Offline
Joined: 2010 Dec 2

I think that it is possible to put a previous OS into a VM, like running High Sierra in a VirtualBox machine, so 32-Bit apps will still be possible. The downside is that you need that extra RAM and that extra time to start and stop the VM all the time.

Apple has a long history of forcing developers to adapt by simply removing support for the older technology. It happend so often already... I also think this is bad, but for Apple it actually turned out well: they are as successful as never before. Aren't they?

3371-Alpha's picture
Offline
Joined: 2016 Mar 15

@24bit: Interesting, but can you control it from the airport menu? Or does it have one of those awful 3rd party prefpane/control panels you have to keep running in the background?

@SkyCapt: Not 100% what I was looking for but interesting (in a really bad way) none the less. Still it's not too surprising, Tim Cook's not the genius Jobs was. In fact I find him to be quite a poor replacement. This is the reason I don't own a new Mac.

24bit's picture
Offline
Joined: 2010 Nov 19

I know what you mean, got an old WiFi USB stick using its own app and activation. Gruesome.
This one is as smooth as it could be.

Wi_FI_10126

3371-Alpha's picture
Offline
Joined: 2016 Mar 15

Now THAT is cool! Just need to find one that's Leopard compatible then.

24bit's picture
Offline
Joined: 2010 Nov 19

A guy over at Insanely posted that BCM94322 chipsets were known to be working in 2009.
Whether this applies to your Leopard rig is hard to tell.
http://www.insanelymac.com/forum/topic/167149-hp-elitebook-8530w-osx86-i... #65
Best look for old Broadcom based hardware as Apple did choose those back in the day.

24bit's picture
Offline
Joined: 2010 Nov 19

I did look into Leopard S/L/E/IONetworkingFamily.kext for the supported Broadcom chipsets.
Looks like this:

Broadcom_10_5

The BCM 4322 cards look like a good choice.
http://www.netcheif.com/Reviews/DSL-2760U/4322_4323-PB01-R.pdf
The Dell card I pointed to has these decice IDs: 14e4/432b, so it will work with the 10.5 IONetworkingFamily.kext.
Obviously, you will need a m PCI-E to PCI-E adapter, no problem with free slots. Smile

There also is Atheros, covering the Athr5424ab based cards.
Maybe the one you already own?

3371-Alpha's picture
Offline
Joined: 2016 Mar 15

Actually the G5 Quad already has a mPCIe, or at least that's implied by the link I referenced at the top for the Airport card.

Edit: Oh crap, Shock you're right! You do need a mPCIe adaptor, misread that part! Even this PowerMac FAQ says the same, and I missed it! Technically speaking, the G5 does use mPCIe for it's Airport, but with a proprietary connector. Damn you Apple!

Oh well, mPCIe adapters aren't too expensive, and combined with this flexible riser "card", you can make use of that second PCIe slot that's normally covered by your double sloter graphics card. Not sure where you could put the card it's self, though if you remove the back plate and don't have a G5 Jive it should be easy to find a place.

24bit's picture
Offline
Joined: 2010 Nov 19

I seem to recall a video instruction by OWC fitting in a PCI-E WiFi card in a G5 - No witchcraft seemed to be needed. Smile I don´t own a G5 though, can´t tell from own experience.

3371-Alpha's picture
Offline
Joined: 2016 Mar 15

This video? Yeah, you could do that, but like I said certain models have those double slot graphics card like the Quadro 4500. Using that witchcraft, you could make use of that covered slot. If you remove the backplate/bracket of the mPCIe to PCIe adaptor it's self, you should be able to find room for it in the case elsewhere, though you'll still need to get some antennas and route them somewhere. You might be able to pass them through the G5's porous case; end result might not be pretty but if you need the upper 2 PCIe slots for something else.....

Edit: turns out I was wrong about one detail, the airport/bluetooth combo card the quad uses actually interfaces through a proprietary form of (standard) mPCI, not mPCIe like I thought. It's actually the same socket type use on earlier G5's just with a "runway" card, in fact you can even use the Airport Extreme card in a late 2005 model. Other useful and interesting information I found while browsing: older (2008 and prior) Mac Pros used the same bluetooth card type as early, pre-quad G5s. Found that out here. It's also readily visible once you know about it: here's the G5 version, and here's the Mac Pro's. It's worth noting, like the quad's, the Mac Pro version is Bluetooth 2.0 where as the G5 version is 1.1. I don't know if they're swappable, but it's likely with the right OS version (only Tiger and Leopard have 2.0 support) they could be. Regardless, this is a thread for late 2005 model myths, so that's a question for another thread.

I have also looked into ways to improve the G5's Bluetooth (using an adaptor that's also seen as native like mentioned before), but unfortunately Apple didn't start using 2.1 until 2009; Wireless N was adopted in 2007 which made it plausible. I suppose 2.0 will have to do.

Oh, I consider the wi-fi card myth confirmed/resolved.

3371-Alpha's picture
Offline
Joined: 2016 Mar 15

I've come with some updates to this old thread. Remember when I said that a use once mentioned a 7900 GTX could work in a G5? Well research is making this seam less feasible now; the 7800 used the G70 chip while the 7900 used the G71. I'm not sure if the G71 added any features but if it did it would make using out of the question as those hacked ROM will be incompatible. It's worth noting that the 7800 has a core speed of 550 MHz and memory speed of 850 MHz (1700 DDR) vs. the 7900's 650 core and 800 (1600 DDR) memory. If that's true then the 7800 should have better memory bandwidth. A reference can be found here. There are several pre-OCed versions of the 7800 card that generally come with the rates of 570 to 580 for the core and 875 (1750 DDR) for the memory. If one can find the right offsets in the ROM uploaded to this site we could make it run at these speeds. Not sure if Graphiccelerator would work correctly with the card but that's also an option. I'd recommend replacing the thermal paste on the card if you do overclock.

Speaking of which, my quad runs quite hot sometimes. It may be possible to fix this by replacing the paste with some high quality Arctic Silver. The LCS fluid could probably be replaced with a better modern standard; I remember reading from a user who rebuilt his G5 LCS that it uses high grade antifreeze for coolant. The same guy also mentioned distilled water would work. Got to wonder if the modern chemical solutions would function correctly. I've also found a way to quiet noisy fans; a guide for applying oil can be found here and here.

fogWraith's picture
Offline
Joined: 2009 Oct 23

Right, the 32GB test on the late 2005 quad was long overdue... as it turns out, the limit for each slot is 2GB, ECC or NON-ECC.

4GB modules will not work, two machines tested and always the same result... three beeps, three blinks and fans on full blast.

But hey, at least I have 32GB RAM for some other project Tongue

SkyCapt's picture
Offline
Joined: 2017 Jan 11

Not til about 2009 that Apple mem controls allow 4GB per module ...

fogWraith's picture
Offline
Joined: 2009 Oct 23

A claim has been made though about a Quad running with 32GB, but the OS only being capable of using 16GB. I'm hoping to receive pictures of the modules so I can use them for reference, but remain sceptical as they are said to be "PC2-4200U-444".

SkyCapt's picture
Offline
Joined: 2017 Jan 11

What is strange about the report? It ought have nothing to do with capacity, the "PC2" represents "DDR2" physicality, the 4200 represents speed (533 MHz normal for G5 Quad) , and the "-444" is like response timing. Not that such reports are trustworthy, they arent. The reports parrot info stored in nvram on each module (the tiny little 8pin chipper on each dimm is an nvram thingy called a "SPuD") and it's perfectly capable of saying one thing while doing another thing. My PowerMac says both "PC-2600" and "PC-2700" but they're two diff names for the exact same speed, so i like to call it PC-2666. Worse, i can use 400 MHz RAM and my AHT correctly says "PC-3200" but the firmware and OSes say "PC-2600" while the speed is constant 3200. I also use some 467MHz modules which AHT says the speed is "Unknown" and more 467MHz modules which AHT calls 3200.

I suspect hoax of 4GB per module in G5 Quad. 32GB is silly anyway. The makers/sellers say "more RAM equals faster computer" but they're biased, the "law of diminishing returns" kicked in well below 32GB. Anyway with an SSD virtual-memory is today as fast as real RAM had been in the past, especially if you don't use the encrypted storage option. Its like having 100,200,or 500GB of RAM already now.

fogWraith's picture
Offline
Joined: 2009 Oct 23

The main difference may be that my modules are buffered, while his are not... and that the Quad simply does not like buffered (4GB) modules, I'd have to find and buy more RAM just for testing this. I've been overly lazy on finding and reading technical documentation I'm afraid.

32GB is in my opinion overkill for the Quad, 8-16GB is more than well enough for the machine whatever you decide to work with.

Each Quad I have are already "maxed out" as per the standard spec sheets from Apple, apart from utilizing an SSD for the system and a larger mechanical drive for storage. I'll have to service the water cooling system on each of the machines though before I do anything else, like buying more RAM Tongue

SkyCapt's picture
Offline
Joined: 2017 Jan 11

I have similar RAM situation but not the Quad model, mine can be called "G5 MirrorDoor/Late 2003 Myths". The Apple spec max RAM is 2GB but I can fit 4GB on board, and its obvious the OS(s) can handle 4GB (if in "G5 mode"). AHT (v2.0.2 and v2.1.0) report 4GB total, the hardware chain: slots, controllers, CPU all support 4GB, the OS supports 4GB, but, in the end it's programmed to be only 2GB.

Still looking for an updated RAM Disk driver, no reason why I can't have 2GB system RAM plus a 2GB RAM Disk.

The buffered/unbuffered business is also shady. It doesn't matter much, just when response timing had been critical, but today's newly minted RAM chips run circles around these old motherboards. New buffered RAM can have faster response than unbuffered so it's idiotic for these motherboard to go about banning buffered RAM.

I have all sorts of buffered and unbuffered modules to play with, some are even buffered and report as unbuffered via their SPD signature. AHT v1 (the MirrorDoor 2002 AHT) bans overt buffered RAM by crash launching with the error message "Invalid memory access" but these same RAM modules function fine in OSX and OS9 go figure. Quite the mess we got from decidedly sloppy manufacture industry.

fogWraith's picture
Offline
Joined: 2009 Oct 23

On a totally unrelated issue, but maybe not really, is one of the issues I've faced on one of my old UltraSPARC machines... I wanted to go for a slightly faster CPU, granted I thought it'd be fine with a simple switch.

Booting the machine, CPU is still at the same speed as previously reported in OpenBoot PROM, a few further tests with various CPU's and attempts at reconfiguring it's still the same - fixed and locked, Solaris reports the same.

A wild punch in the dark, could, perhaps the hardware be unlocked by hacking firmware (for Mac too)? Even if the thought might be stupid, I'll just put it out there Tongue

SkyCapt's picture
Offline
Joined: 2017 Jan 11

Looks like there are firmware tests. I've a C2D/DDR2 Mac that Apple says is 666 MHz RAM. Unlike my MirrorDoor that runs RAM at any speed (asynchronous, it by default seeks the highest common speed between mobo and RAM chips), the DDR2 remains asynchronous, scaled up by a factor of two in all regards, but in order to boot 800 MHz RAM I must obtain 800 MHz RAM which reports itself as being 666 MHz. Fortunately the 'industry' is bored with just having 666 memory stop at 666 mhz and so easily fifty percent of new 666 ram can and does step up to 800 MHz. What's more, I tested my C2D/DDR2 has not two but three distinct memory speeds and I believe the best of them three is 933 MHz RAM = 2x the 467 MHz RAM that my MDD/DDR1 has.

3371-Alpha's picture
Offline
Joined: 2016 Mar 15

Sorry to hear that the test didn't return positive results. At lest we know now I suppose.

MacTouch's picture
Offline
Joined: 2016 Mar 19

I've a C2D/DDR2 Mac that Apple says is 666 MHz RAM.

Well, I have to "refresh" my old own memory. Tongue I have a C2D myself & it says 667 MHz RAM & not 666. So I presume this last number was replaced because... it's referred to the "number of the beast" Evil ? But, may be I guess another serious explanation... Smile

SkyCapt's picture
Offline
Joined: 2017 Jan 11

NOTB, yeah. But 666 and 667 mean the same, 666.66 rounds up to be 667. Btw didn't the first ever Apple I computer retail for $ 666 or 666.66

MacTouch's picture
Offline
Joined: 2016 Mar 19

Ah, yep, thank you, SkyCapt. I was not aware that Apple has sold "devil's" computers for $ 666... Smile

Jatoba's picture
Offline
Joined: 2018 Apr 16

Not sure if you guys knew about this, but the YDL PowerStation, which uses almost the exact same hardware as the Quad G5, is reported to be capable of handling 32 GB RAM. This always made me wonder if the 16 GB limit was somehow a limitation forced in Mac OS X Tiger/Leopard or even in some ROM within the Quad G5 (if any).

As for ECC and buffered RAM, I forgot where I saw it, but reports I read stated the G5s accept ECC RAM, unlike any previous PowerPC Mac, as well as non-ECC, but it will not accept any buffered RAM. Only unbuffered, as with any PowerMac, AFAIK.

I personally purchased 2x8 GB non-ECC RAM sticks, because ECC, while more reliable, is slightly slower (perhaps negligibly so?).
Then again, SkyCapt's idea to use only 2 sticks of 1 GB RAM each is probably the best as far as that goal is concerned. Smile (I think I'd prefer to still have 4 or 8 GB of RAM at the very least, though, so I'd likely prefer to keep my 2 GB sticks in there.)

Now question: How does one go about overclocking RAM? Has anyone successfully done that for their Mac, particularly the G5s or even the Quad G5 specifically?