MAC PRO Early 2008 supported RAM modules

Question

AndreL1970 Author

Level 1

8 points

MAC PRO Early 2008 supported RAM modules

Hi folks,

I have a MAC PRO Early 2008 with a mixture of RAM modules, but I want to upgrade it to more total RAM.

Actually I have the following modules installed:

2x HYNIX 1GB 2Rx8 PC2-6400F 555 11 HYMP512A72CP8D3-S5 AB-T

2x KINGSTON 1GB 2Rx8 PC2-6400F 555-10-R0 1,8V KTA-MP800K2/2G

2x KINGSTON 2GB 2Rx4 PC2-6400F 555-11-U0 1,8V KVR800D2D4F5/2G

In total these are 8GB RAM but totally not good configured, because 4 modules are on one board and the other 2 are on the second memory board.

I want to remove all of the above modules and lift the RAM to 32GB by inserting 8x 4GB modules.

I have tested now 2 different types and no type is accepted by the MAC PRO.

These are the types that are not working:

HYNIX 4GB 2Rx4 PC2-6400F-555-11 HYMP151F72CP4D3-S5 AB-C

and another HYNIX with 666 that I returned because I thought that was the reason why the modules are not working in MAC PRO.

I have no idea what is going wrong.

The actual working config is a absolutely problematic config with different brands and 2Rx4 & 2Rx8 modules and works without any trouble and a clean config with 8 modules of the same type is not working.

RAM config guideline shows only: MAX 32GB total, 800MHz, DDR2, FB-DIMMS, 72Bit, 240pin, max 36 chip, ECC

Please give me some advice to solve that problem.

Thank you all

Andre

Mac Pro, OS X Mavericks (10.9.5)

Posted on Oct 21, 2017 3:04 AM

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Answer 1

Oct 21, 2017 10:53 AM in response to AndreL1970

There are many different ways to obtain DIMMs that appear to be correct, that seem to match the specs, and are likely perfectly good DIMMs. But many of these "seemingly correct" DIMMs will simply not work in the very fussy Mac Pro 2008 model.

You can spend many days researching DIMM construction and memory timing to become an expert with the ability to predict which DIMMs will work and which will not. This may involve buying (and hopefully returning for refund) MANY sets of DIMMs.

There are also DIMMs that will work for a while, but due to small heatsinks, will self-destruct in a fairly short time when used in a Mac Pro. There are also DIMMs which do not contain Apple-approved temperature sensors. These will cause your Mac Pro to run its fans on maximum at all times.

What readers here find MUCH more useful is to deal with a vendor who is already an expert on which DIMMs work in these Macs. Rather than buying and returning multiple sets, to purchase DIMMs guaranteed to work in a Mac Pro 2008 model.

If you could share what area of the world you buying in, Readers would be happy to suggest vendors who can provide these DIMMs, guaranteed to work.

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Answer 2

Eau Rouge

Level 8

42,678 points

Oct 21, 2017 3:46 AM in response to AndreL1970

It is very important to get the correct RAM modules for the 2008 MacPro

you cannot buy just any DDR2 RAM it must be the ones with the large heat syncs on and specifically say it is for Apple

Have a look at this page from Mr Memory, https://www.mrmemory.co.uk/memory-ram-upgrades/apple/mac-pro/2008-2.8ghz-quad-co re-intel-xeon the Hynix RAM modules you describe do no look like they are suitable for the 2008 MacPro, the heatsinks do not look correct. The Kingston modules look correct, does you mac work better without the Hynix in? Do you not have thee original Apple modules that came with the Mac.

OWC in the States has RAM for the 2008, Mac Pro Memory Upgrades Up to 128GB

The correct RAM for the 2008 is still quite expensive and getting more difficult to get.

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Answer 3

Eau Rouge

Level 8

42,678 points

Oct 21, 2017 5:41 AM in response to AndreL1970

The RAM modules have to have been made for the MacPro 2008 in mind, just because the RAM is the same spec it may not be suitable for use in the 2008. When you bought the RAM did you check that was definitely suitable for the 2008 MacPro.

Read the HeatSink paragraph in this article, https://www.macmemory.com/collections/mac-pro-memory-for-models-3-1

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Answer 4

AndreL1970 Author

Level 1

8 points

Oct 21, 2017 4:37 AM in response to Eau Rouge

Hello,

the large heat sinks could´t be the reason.

The installed 2GB Kingston modules have also only normal metal plate heat sinks and work.

What is the technical difference between the models, because the modules are all Full Buffered and have ECC.

Bus Speed is 800MHz and timing is also the same.

What is missing on some modules?

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Answer 5

AndreL1970 Author

Level 1

8 points

Oct 21, 2017 6:00 AM in response to Eau Rouge

Sorry, but I do not need any store for buying the RAM modules.

I would like to know the technical reason for the behavior.

The specs for a mechanical heat sink dimension are not part of the problem.

This would be in a working condition a thermal or sound problem because of louder fan rotations.

So please let me know what specifications are the difference when a RAM is made for the MAC.

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Answer 6

Eau Rouge

Level 8

42,678 points

Oct 21, 2017 6:22 AM in response to AndreL1970

When you bought your RAM did you check that it was suitable for the 2008 MacPro.

Did you read the bit about heatsinks, in the article I linked too, the heatsinks need to be of a type to dissipate the extreme heat generated in the 2008, using the incorrect RAM modules will increase fan speed and reduce performance.

When you have installed the RAM you bought are there any red LEDS showing on the memory boards?

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