Sidebar Sidebar
Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.

MacPro 3,1 - RAM or Riser issue?

cwphoto

cwphoto

macrumors newbie
Original poster
Feb 11, 2010
9
0
UK
Hey guys,

So I have a Early 2008 MacPro 3,1 2x2.8Ghz Quad Core Xeon running OS X 10.10.5.

I noticed it was running a bit laggy and was acting up a lot. Looking it over I noticed that it only registered 6GB of RAM instead of the 10GB installed. So I went ahead and ordered 32GB of RAM for it, as I figured I could get more time out of my machine instead of upgrading...and I don't really have the money to drop on a brand new MacPro etc.

Anyway, new RAM came and long story short...Cheap RAM from Amazon and it is going back. Lots of issues.

But now that I am reinstating the old RAM I wanted to see what you guys thought about whether it may be a RAM problem or the riser.

Riser A shows a red light for DIMM 2 and registers as 'empty' and riser B seems fine. I moved the RAM to Riser A's slot 3 & 4. No light, but still registers as empty.

I also tried different matching pairs of DIMMs in Riser A and the light would come on if in Slot 1 & 2, registering as 'empty'. If in slot 3 & 4 nothing registers.

I have yet to run a RAM diagnostic as I am looking for my Apple Hardware Test DVD that came with the tower.

Anyway, it is late and I hope I made some sense. Would love to hear your thoughts!

-CW
 
I had issues with the riser cards on my old 3,1 as well. I had to repeatedly pull, reinsert, and boot to see if they would get recognized. Once they were recognized, they would continue to work flawlessly until I pulled the riser card out again.
 
Thanks for the info. Yeah, I am going to clean it all real good and hopefully that helps. Would like to up my RAM but can't find a reputable place that sells 4GB DDR2 800Mhz DIMMs. I'll see if the cleaning helps and if not try a new riser card.
 
cwphoto said:
Thanks for the info. Yeah, I am going to clean it all real good and hopefully that helps. Would like to up my RAM but can't find a reputable place that sells 4GB DDR2 800Mhz DIMMs. I'll see if the cleaning helps and if not try a new riser card.
Click to expand...
There are loads of cheap 667MHz FB-DIMMs on eBay pulled from Dell & HP Xeon servers. They cost around $100 for 32GB (8x4GB). The performance is all but identical to the pricey Apple-exclusive 800MHz FB-DIMMs. Some of the sellers will guarantee that they work in a Mac Pro.
 
Yeah, I've heard that the difference in speed is less than 4% and pretty much nil in Photoshop etc. The RAM I returned to Amazon, Komputerbay brand, was 667mhz. It was £98 for 32GB, but some of it was DOA. I could get 24GB at most to register. Now they seem to have upped it to £95 for 16GB...http://www.amazon.co.uk/gp/product/B005HIWDHI?psc=1&redirect=true&ref_=oh_aui_detailpage_o08_s00

Do the DIMMs absolutely, if they are the 667mhz modules, need the big heatsinks on them? I've been finding a few other types, but they don't have the heatsinks. Just wanted to make sure. I've found lots like these: http://www.ebay.co.uk/itm/8GB-2x4GB...137347?hash=item35e00bd083:g:Bi4AAOxyirJSGL8J

Thanks for the input! It's really helpful. :)
 
As an Amazon Associate, MacRumors earns a commission from qualifying purchases made through links in this post.
cwphoto said:
Yeah, I've heard that the difference in speed is less than 4% and pretty much nil in Photoshop etc. The RAM I returned to Amazon, Komputerbay brand, was 667mhz. It was £98 for 32GB, but some of it was DOA. I could get 24GB at most to register. Now they seem to have upped it to £95 for 16GB...http://www.amazon.co.uk/gp/product/B005HIWDHI?psc=1&redirect=true&ref_=oh_aui_detailpage_o08_s00
Click to expand...

Komputerbay are crooks. Did you see the review that I put on that Amazon listing? I had a similar experience with DOA DIMMs. It was a lot of hassle getting a refund & I had to invoke the Amazon A-Z Guarantee in the end. It took 4 weeks to get my money back. I suggest that you add a 1* review too to watn off others. There have been other reprts on this forum about this company.
 
As an Amazon Associate, MacRumors earns a commission from qualifying purchases made through links in this post.
Have you tried moving the sicks to Riser B to see how they behave?

I would use sticks with the larger heatsinks. I've tried Hynix sticks with normal server heatsinks and my Mac did not like them. I'm currently using 667's from my 2,1 MP and using them in my MP 3,1 with no issues and they have the required heatsinks. Without your hardware disks you could try running memtest in verbose mode. Takes forever. Not sure if it will point to the problem or not.

I'm actually planning on selling this 3,1 and get a 4,1. Faster everything and lots of upgrading choices
 
I also am thinking I may have a bad memory riser card so I will probably order a replacement one...
 
I just upgraded my Mac Pro 3,1 to 64GB (8x8GB) then down to 56GB (6x8GB = 2x4GB) for reasons explained in this thread https://forums.macrumors.com/thread...low-disks-while-48-gb-fast-disks-why.1940030/ I had a terrible time initially getting the memory to be recognised at all. It's a while since I mucked about with RAM on the 3,1 but it seems that every time I do I have the same performance that I end up seating & re-seating the risers &/or the memory because there is an error or some or all of the memory doesn't work or isn't recognised. I don't know what other people's experience is but this seems to happen most times & tonight I thought at first that I had screwed the system as I couldn't even get the startup chime but I eventually had one fully populated riser working then swapped that into the other riser slot to confirm that both slots were OK then I cleaned the contacts on the other riser seated & re-seated the memory & now it all works. I suggest that the OP get wiggling & re-seating & see if that fixes the problem.
 
nigelbb said:
It's a while since I mucked about with RAM on the 3,1 but it seems that every time I do I have the same performance that I end up seating & re-seating the risers &/or the memory because there is an error or some or all of the memory doesn't work or isn't recognized.
Click to expand...

This was exactly what I experienced with my old 3,1. Once all the RAM was recognized, it would continue to work fine until I pulled out a riser card again.
 
Riser card issues here too.

Even carefully moving the machine from one room to another caused a riser card to be problematic until being reseated a number of times.
 
You must log in or register to reply here.
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.
Top Bottom
Back