MP 1,1-5,1 How long do your FB-DIMMs last?

[EugW]

I have a ton of OEM Hynix FB-DIMMs for my two Mac Pros - 1,1 flashed to 2,1. However, I can't use them because I get kernel panics in El Capitan. They are 512 MB and 1 GB sticks. I have wondered if it's just because the RAM has gone bad, but the consensus is that it's because there is some sort of incompatibility between El Capitan on these Macs and FB-DIMM sizes below 2 GB.

However, after working through my issues with the Let's Encrypt SSL certificate fiasco, I have determined my other RAM with the big Apple type heatsinks is also unstable. I have a number of 2 GB and 4 GB sticks wth the big heatsinks but they are all third party no-name brand RAM. I don't know if it's cumulative heat related problems (which I've often had with no-name brand RAM on other machines), or if it's because it's somehow due to me inadvertently zapping the RAM when I was testing it. I suppose that's possible too. (I was testing the RAM just to make sure the SSL issue wasn't somehow hardware related, but I found out later it's all software related.)

Now I'm running 2 x 4 GB Kingston server FB-DIMMs. It works fine, but of course without those big heatsinks, whenever the computer does something the least bit intensive, the fan ramps up.

I'm now considering buying more RAM with the big heatsinks, but if the RAM tends to overheat and die, I won't bother. Big name brand new FB-DIMMs cost a small fortune, so I'm looking at used or no-name RAM again. In that context I may get nothing and just stick with the server RAM for now and deal with the fan noise, until I have a better lay of the land for the new Apple Silicon Mac minis coming, hopefully sooner than later.

How long does Mac Pro FB-DIMM RAM last for you guys? What brands do you use?

 

[joevt]

I just go to macsales.com (OWC), click My Upgrades, select my Mac, click Memory Upgrades, and choose how much I want. You can get 32 GB for $240.

I'm not sure I've ever had RAM go bad. Usually, it's bad when you get it or it's good.

 

[Petri Krohn]

Now I'm running 2 x 4 GB Kingston server FB-DIMMs. It works fine, but of course without those big heatsinks, whenever the computer does something the least bit intensive, the fan ramps up.

I'm now considering buying more RAM with the big heatsinks...

Just move the heatsinks from your 512 MB and 1 GB DIMMs to your 4 GB and 8 GB DIMMs.

There is a thermal pad between the heatsink and the DDR2 ram modules. It can be reused. But you need to apply fresh thermal paste between the heatsink and the Advanced Memory Buffer (AMB) chip.

What brands do you use?

I just buy used server ram from eBay. I have received Samsung and Micron, both good enough for me.

I have paid £10 ($13) for 4 x 4 GB or £20 for = 4 x 8 GB. Prices have since gone up and 8 GB modules have become unavailable.

...consensus is that it's because there is some sort of incompatibility between El Capitan on these Macs and FB-DIMM sizes below 2 GB.

Yes, I ran into the same issue when I first tried to boot El Capitan.

***

Mac Pro 3,1 issues

I believe it is possible to flash the cheap 667 MHz FB-DIMMs to run at 800 MHz on the Mac Pro 3,1. The second generation chips used on 4 GB and 8 GB modules are more than capable of running at 800 MHz (4.8 Gbits serial link speed). Even the first generation controller chip from Intel from 2006 is capable of operating at 800 MHz. (See Intel® 6400/6402 Advanced Memory Buffer.)

For starters, read this:

Modifying RAM SPD Data

Modifying RAM SPD EEPROM data to force the operating frequency.

blog.zakkemble.net

P.S. - I analyzed a Kingston FB-DIMM I had opened (labeled KTA-MP667K2/1G for the 1 GB kit). The nine DDR2 chips are labeled ELPIDA E5108AGBG. They are 667 MHz chips. The Advanced Memory Buffer is labeled IDTAMB0480. The data sheet says it can only operate up to 4 Gbit/s serial speeds (667 DRAM). All typical 667 MHz technology from 2006. I still have not checked my newer Samsung and Micron DIMMs.

I opened one of my Micron 4 GB modules, labeled MT36HTF51272FZ-667H1D6 (4GB 2RX4 PC2-5300F-555-12-E0) It has two rows of DDR2 memory chips on both sides, a total of 4 x 9 = 36 chips. The chips are labeled OEHI2 / D9LHM. The last part is a "FBGA Code". Using the on-line "FBGA and Component Marking Decoder" on the Micron site, it translates to the part number "MT47H256M4CF-25E:H". The second to last part, 25E is a speed code. The data sheet says it is capable of operating at 800 MHz at CL5.

The Advanced Memory Buffer on the Micron DIMM is marked IDTAMB 0680L4RJ. Jotrin has the data sheet behind a password. Digikey lists the part as AMB0680L4RJ and links to the flyer that says 800 MHz / 4.8 Gbits serial speed.

I believe people selling 800 MHz memory for the Mac Pro 3,1 are just repacking and reprogramming used server RAM.

 

[Macschrauber]

I also came across a few 667 modules what simply ran on 800 in a Mac Pro 3,1

guess when stock gets low some brands simply labeled their modules as 667.

 

[EugW]

I just go to macsales.com (OWC), click My Upgrades, select my Mac, click Memory Upgrades, and choose how much I want. You can get 32 GB for $240.

I'm not sure I've ever had RAM go bad. Usually, it's bad when you get it or it's good.

I don't live in the US, so the cost is higher. Also, OWC is a second tier RAM vendor. They have a good warranty, but if it's a main production machine I'd rather buy from someone like Crucial, a top tier vendor, or else get Crucial or Samsung RAM from a local 3rd party vendor. That said, for this particular machine, OWC would be more than fine.

Anyway, the price is the issue. It's an old Mac Pro and I'm debating whether I should just retire it or not. For the price of 16 GB RAM in Canada, it might just make more sense to put the money towards a new Mac mini, or else even replace my 27" 2017 iMac with a new hypothetical 30" iMac.

The 27" iMac is currently my home machine. I have my entire life on that machine. My Mac Mac Pro sits on the same desk and I use it for mainly business apps, for work. It's hooked up to a 30" Cinema HD Display.

I could get a 30" iMac and use the Cinema Display as a secondary monitor, or else just retire that Cinema Display too. 30" seems to be a good size for me. I don't really need two 30" screens, but I found 27" just a touch small. I was using two 27" iMacs for the longest time, one as a secondary monitor.

Just move the heatsinks from your 512 MB and 1 GB DIMMs to your 4 GB and 8 GB DIMMs.

There is a thermal pad between the heatsink and the DDR2 ram modules. It can be reused. But you need to apply fresh thermal paste between the heatsink and the Advanced Memory Buffer (AMB) chip.

I tried that a while back. I couldn't get the heatsinks off, either the server RAM or the Apple-specific RAM. I think some of them may be using thermal glue. For one of the server RAM sticks I saw a little of the thermal compound sticking out from under the heatsink so out of interest I tried scraping it off. It was hard as a rock. Not thermal paste and definitely not part of a thermal pad, so I concluded it was thermal glue.

For another stick I tried sticking smaller heatsinks on top of the existing heatsinks of the server RAM, but that didn't seem to help anything at all.

So I gave up on that idea.

I just buy used server ram from eBay. I have received Samsung and Micron, both good enough for me.

I have paid £10 ($13) for 4 x 4 GB or £20 for = 4 x 8 GB. Prices have since gone up and 8 GB modules have become unavailable.

I don't think I can use 8 GB modules since it's a MacPro1,1/2,1, with 2 x quad-core 3.0 GHz Xeon X5365 (total 8 cores). But that's OK since I don't really need much memory for this machine. 8 GB is OK, and 16 GB is way more than I need on this machine. (I have 24 GB on my iMac.)

I'm getting more used to the fan ramp up though. It happens at bootup, and also happens when I visit multimedia-heavy websites and if I'm watching 1080p60 or 1440p YouTube. But for most mainstream YouTube streams at 720p or 1080p it's usually OK. And if I'm just using my business apps, the fan usually stays inaudible.

Interestingly, I have another Mac Pro which had 2 x dual-core 2.66 GHz Xeon 5150 chips (total 4 cores) but for which I swapped in relatively low power 2 x quad-core 2.33 GHz Xeon E5345 chips (total 8 cores), totally cleaned it all out, and applied new thermal paste an all that. However, using the same server RAM, that machine is no quieter than my dual 3.0 GHz Xeon X5365 machine, but the 3.0 GHz machine is noticeably faster. And when using proper Apple style RAM, both the 2.33 GHz machine and the 3.0 GHz machine are completely silent.

 

[zohaibhasan]

I have a ton of OEM Hynix FB-DIMMs for my two Mac Pros - 1,1 flashed to 2,1. However, I can't use them because I get kernel panics in El Capitan. They are 512 MB and 1 GB sticks. I have wondered if it's just because the RAM has gone bad, but the consensus is that it's because there is some sort of incompatibility between El Capitan on these Macs and FB-DIMM sizes below 2 GB.

However, after working through my issues with the Let's Encrypt SSL certificate fiasco, I have determined my other RAM with the big Apple type heatsinks is also unstable. I have a number of 2 GB and 4 GB sticks wth the big heatsinks but they are all third party no-name brand RAM. I don't know if it's cumulative heat related problems (which I've often had with no-name brand RAM on other machines), or if it's because it's somehow due to me inadvertently zapping the RAM when I was testing it. I suppose that's possible too. (I was testing the RAM just to make sure the SSL issue wasn't somehow hardware related, but I found out later it's all software related.)

Now I'm running 2 x 4 GB Kingston server FB-DIMMs. It works fine, but of course without those big heatsinks, whenever the computer does something the least bit intensive, the fan ramps up.

I'm now considering buying more RAM with the big heatsinks, but if the RAM tends to overheat and die, I won't bother. Big name brand new FB-DIMMs cost a small fortune, so I'm looking at used or no-name RAM again. In that context I may get nothing and just stick with the server RAM for now and deal with the fan noise, until I have a better lay of the land for the new Apple Silicon Mac minis coming, hopefully sooner than later.

How long does Mac Pro FB-DIMM RAM last for you guys? What brands do you use?

FB-DIMMs, like most memory modules, have a long lifespan and can last for many years if used under
<a href="https://www.dyethin.com/productdetails/future-designs-inc-somdimm-rx63n">normal</a>
conditions. However, their longevity can be influenced by factors such as operating temperatures, usage patterns, and overall system maintenance. Typically, well-maintained FB-DIMMs can last anywhere from 5 to 10 years or more before any potential issues arise. Regular system checks and ensuring proper cooling can help extend their lifespan even further.