eos1x

macrumors newbie
Original poster
Dec 23, 2015
25
1
Hi Everyone,

I'm hoping I can get a little help here.

I have seen in the forum that a number of people are using 64GB of RAM in Mac Pro 3,1.

I am trying to figure out the exact specs needed to do so.

I have done multiple searches and I understand the ram is 667Mhz and must be 2RX4 PC2 5300F.

https://forums.macrumors.com/threads/64gb-ram-in-2006-mac-pro-2-1.1939624/#post-22279890

https://forums.macrumors.com/threads/8gb-fb-dimms-for-2006-2008-mac-pro-which-ones-work.1549628/

My question is should it be 8GB 2RX4 PC2 5300F 555-11 or 8GB 2RX4 PC2 5300F 555-12. Perhaps both 11 and 12 work?

For example, would this work

http://www.ebay.com/itm/Kit-of-64GB...476102?hash=item5b1df2cfc6:g:JUIAAOSwu4BVsrBp

If anyone who has done this upgrade would be willing to share the exact specs to help find the appropriate modules on ebay I would be very grateful.

Thanks in advance,
Rory
 

jmp473

macrumors newbie
Apr 25, 2011
27
2
Atlanta
Have had some of the same questions myself. But, could only afford to fill the 4 empty slots in my 3,1 . Anyway! I Just now decided I'd better take a chance on these 4 (low-buck) 4x8GB's: http://alturl.com/7egaq (wish me luck o_O)

Some of the 8GB 2RX4 PC2 5300 555-12's I've seen listed were actually 5300P's - but wasn't able to confirm anything from a reliable source.
 

eos1x

macrumors newbie
Original poster
Dec 23, 2015
25
1
Thanks nigelbb and jmp473.
Good luck! jmp473. I'd be really interested to know how you fair with your purchase. Do you have the ram in hand or are you still waiting for it?
 
Last edited:

eos1x

macrumors newbie
Original poster
Dec 23, 2015
25
1
I have another question. I am seeing ram listed on ebay as 8GB 2RX4 PC2 5300F 555-11- AC or 8GB 2RX4 PC2 5300F 555-11 D0 or 8GB 2RX4 PC2 5300F 555-11 J0. Are the two last digits of any relevance here?

Happy Holidays Everyone!!
 
Last edited:

jmp473

macrumors newbie
Apr 25, 2011
27
2
Atlanta
Thanks nigelbb and jmp473.
Good luck! jmp473. I'd be really interested to know how you fair with your purchase. Do you have the ram in hand or are you still waiting for it?

The RAM arrived Monday. Looked new. I installed it yesterday, it showed up correctly 36 GB (new 32 + old 4) and today has passed all Rember tests.
So far so good!!! I couldn't be happier! especially considering the price.

All RAM is listed at 667MHz (down from 800 MHz) but there's a definite speed increase and with just 4 GB I was having some crashes - none since. Apple says 2 GB RAM is minimum for El Capitan. But, regular with use of just Safari alone and in fact right now, Activity Monitor is showing 7+ GB being used. 4 GB for me was obviously not enough.

Also, there's been no noticeable increase in fan or heat (but it has only been about 70° F inside and it is still early days. Still... the RAM was shipped promptly, came well packaged, package has this on outside: "Something Wrong? Let us make it right!" "Your 100% satisfaction is our goal" - with their eBay ID etc. and a number to call. That's great to see on a budget item.
 
Last edited:

eos1x

macrumors newbie
Original poster
Dec 23, 2015
25
1
Glad to hear it all worked out for you jmp473. It's encouraging to know that those specs work well.
 

eos1x

macrumors newbie
Original poster
Dec 23, 2015
25
1
For anyone who may be looking for specs. I ordered the following 8GB 2RX4 PC2 5300F 555-11 ram modules on ebay for my Mac Pro 3,1
Screen Shot 2016-01-04 at 3.14.50 PM.png


So far, so good, they work.

I order 48GB as I also want to add a Samsung SM951 and 56GB is apparently the max you can use with it in a 3,1.

https://forums.macrumors.com/thread...e-48-gb-fast-disks-why.1940030/#post-22360887

Screen Shot 2016-01-04 at 4.21.15 PM.png
 
Last edited:

David.Dav

macrumors newbie
Dec 2, 2017
2
0
For anyone who may be looking for specs. I ordered the following 8GB 2RX4 PC2 5300F 555-11 ram modules on ebay for my Mac Pro 3,1
View attachment 608776

So far, so good, they work.

I order 48GB as I also want to add a Samsung SM951 and 56GB is apparently the max you can use with it in a 3,1.

https://forums.macrumors.com/thread...e-48-gb-fast-disks-why.1940030/#post-22360887

View attachment 608788

If I might pick your brain...

Does it matter that yours are 667MHz over the recommended 800MHz?

I am trying to find RAM to buy on line but not really sure about the different subtle variations. Also I notice a lot have "FOR SERVER ONLY" in their titles. Does this make a difference you think?
 

h9826790

macrumors P6
Apr 3, 2014
15,267
7,559
Hong Kong
If I might pick your brain...

Does it matter that yours are 667MHz over the recommended 800MHz?

I am trying to find RAM to buy on line but not really sure about the different subtle variations. Also I notice a lot have "FOR SERVER ONLY" in their titles. Does this make a difference you think?

My understanding is, cMP can use BOTH server RAM and normal PC RAM. But a normal PC CANNOT use sever RAM. That's why the seller usually clearly state that to avoid trouble from PC users.

For cMP user, get the server RAM usually better and cheaper than buy the PC equivalent RAM. Because server usually upgrade quickly and lack of PC market make their old stuff really valueless. And at the same time, old server parts usually more reliable, even they are now cheaper than PC equivalent parts.

Clock speed doesn’t really that matter, the cMP will automatically run the DIMM at the max available speed. And since different speed will associate with different latency. The real world performance difference usually very small (e.g within 2%).
 

David.Dav

macrumors newbie
Dec 2, 2017
2
0
My understanding is, cMP can use BOTH server RAM and normal PC RAM. But a normal PC CANNOT use sever RAM. That's why the seller usually clearly state that to avoid trouble from PC users.

For cMP user, get the server RAM usually better and cheaper than buy the PC equivalent RAM. Because server usually upgrade quickly and lack of PC market make their old stuff really valueless. And at the same time, old server parts usually more reliable, even they are now cheaper than PC equivalent parts.

Clock speed doesn’t really that matter, the cMP will automatically run the DIMM at the max available speed. And since different speed will associate with different latency. The real world performance difference usually very small (e.g within 2%).

Thank you for the explanation!
 
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.