Late 2005 Memory - AMD Only DDR2

[MisterKeeks]

Looking to put 16GB in a Quad G5. I've noticed that there are a lot of Chinese listings on ebay advertising DDR2 that is only compatible with AMD systems. I'm wondering what the technical reason for this is, and if it might be possible to use them on PowerPC systems.

Does anyone know what is the technical difference between these and normal DDR2 modules is/are?

 

[AphoticD]

I don’t know what the specifics for AMD compatibility are, but these are the sticks I bought to max out my DC G5 in late ‘16 (16GB);
https://www.ebay.com/ulk/itm/281801341172
(Not my listing)

The G5 is still going strong on almost a daily basis, no faults.

 

[LightBulbFun]

Looking to put 16GB in a Quad G5. I've noticed that there are a lot of Chinese listings on ebay advertising DDR2 that is only compatible with AMD systems. I'm wondering what the technical reason for this is, and if it might be possible to use them on PowerPC systems.

Does anyone know what is the technical difference between these and normal DDR2 modules is/are?

I have thought about this myself a bit

from what I understand/have read about, the whole AMD thing comes from some timing stuff, and that these AMD sticks run a bit "out of spec" at their "Rated" speed which makes them incompatible with intel chipsets.

however the Memory controller in the PCIe G5s (U4 Kodiak CPC945) always runs the RAM at 533Mhz so I wonder if these sticks would work in a PCIe G5 seeing as they are being under-clocked which might bring them back into spec...

 

[Hrududu]

Tried some of the AMD only DDR2 in my QC G5. To borrow form the meme, "Sounds good, doesn't work."

 

[MisterKeeks]

I have thought about this myself a bit

from what I understand/have read about, the whole AMD thing comes from some timing stuff, and that these AMD sticks run a bit "out of spec" at their "Rated" speed which makes them incompatible with intel chipsets.

however the Memory controller in the PCIe G5s (U4 Kodiak CPC945) always runs the RAM at 533Mhz so I wonder if these sticks would work in a PCIe G5 seeing as they are being under-clocked which might bring them back into spec...

That's really what I'm wondering... I'm hoping it's more that they are incompatible with most Intel chipsets, rather than only compatible with AMD.

Tried some of the AMD only DDR2 in my QC G5. To borrow form the meme, "Sounds good, doesn't work."

That's a shame. We may never know why I guess.


I'm tempted to buy some of the AMD only stuff, if only to tempt fate a bit. It's not about cost savings, it's more about the principle of the thing

 

[LightBulbFun]

That's really what I'm wondering... I'm hoping it's more that they are incompatible with most Intel chipsets, rather than only compatible with AMD.




That's a shame. We may never know why I guess.


I'm tempted to buy some of the AMD only stuff, if only to tempt fate a bit. It's not about cost savings, it's more about the principle of the thing

I have read reports of some of these "AMD only" sticks working on some intel motherboards but that most of the time they are quite un-stable however reducing the clocks and upping the timings (from 555 to 666 for example) tends to stabiles things again it seems

@Hrududu which sticks did you try exactly? (ie capacity etc) because while I have read reports of 4GB DDR2 sticks working in PCIe G5s and I have 4 Samsung ones which are proper memory sticks not some AMD only stuff, but sadly while my G5 Quad will chime with those sticks, it will then beep at me 3 times no banks pass POST, I have never had a mac complain after the chime like this before...

 

[dbdjre0143]

Can't comment on their usage in the G5, but I did buy a 16 GB set of that AMD-only stuff a couple years ago for use in my Phenom X4 desktop. They were a bit on the unstable side (would fail in a Prime95 memory test anywhere from 12-24 hours in) until I down-clocked them a bit. After adjusting, I made it over 48 hours without issue in Prime95, so didn't test further. Been using them for over two years since that without issue. Mine were actually Samsung-branded.

 

[mmphosis]

Power Mac G5 (Late 2005)

Main memory 512MB of 533MHz DDR2 SDRAM (PC2-4200); supports up to 16GB

There's some PowerPC Mac interest on hacker news today: https://news.ycombinator.com/item?id=17229793

 

[Hrududu]

I have read reports of some of these "AMD only" sticks working on some intel motherboards but that most of the time they are quite un-stable however reducing the clocks and upping the timings (from 555 to 666 for example) tends to stabiles things again it seems

@Hrududu which sticks did you try exactly? (ie capacity etc) because while I have read reports of 4GB DDR2 sticks working in PCIe G5s and I have 4 Samsung ones which are proper memory sticks not some AMD only stuff, but sadly while my G5 Quad will chime with those sticks, it will then beep at me 3 times no banks pass POST, I have never had a mac complain after the chime like this before...

I couldn't say exactly what they were. I still have 1 or two of them, but they are in my shop 2 hours away. Next time I'm out there, I can snap a photo. They were some low profile PC2 6400 2GB sticks. At the time, the price was good and I had people with AMD PCs that would come in looking for RAM upgrades. Naturally I had to toss some in the G5 just in case it would work, but they didn't.