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 Post subject: Mac Pro RAM layout?
PostPosted: Mon Sep 03, 2018 10:36 am 
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Got a Mac Pro 2010, no video, but white light on power button, green light on Video card/Quadra 4000, I feel drives spinning.

8 seconds after power applied get red light on rear RAM riser. Thing is it has 6 RAM sticks, 4 front filled, but only 2 sticks on rear riser... will it run that way?

Does the RAM need pairs? Kos the red LED good?


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 Post subject: Re: Mac Pro RAM layout?
PostPosted: Mon Sep 03, 2018 5:05 pm 
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If the computer boots up, it's fine. What is your CPU configuration in the machine?

Here are instructions on which DIMM slots to fill in what order on these machines.

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 Post subject: Re: Mac Pro RAM layout?
PostPosted: Mon Sep 03, 2018 5:44 pm 
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The Mac Pro uses a three-channel memory controller, meaning it runs the fastest with three identical DIMMs installed in the first three slots. I don't know the rules for dual CPUs because, well, I haven't encountered one... the only Mac Pros at work with dual CPUs are 1,1 because they couldn't be bought any other way. They really needed dual CPUs the entire time, but they don't actually understand technology so they got single CPUs. :roll:

It sounds like someone got a dual three channel kit and installed them wrong. Tia's article is spot on in terms of what to install where, although its sometimes confusing. I've had to correct more than a few people who thought they could skim it instead of read it.


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 Post subject: Re: Mac Pro RAM layout?
PostPosted: Mon Sep 03, 2018 6:06 pm 
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Thnks.

It's 12 core Dual 2.93 GHz.

So, do I take it that they can still boot with less than optimal arrangements? Like 4 & 2?

How do you tell if it's booting or not without any video?


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 Post subject: Re: Mac Pro RAM layout?
PostPosted: Tue Sep 04, 2018 8:55 am 
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I would try installing just two DIMMs and see if it works.

Its possible the video card has been baked to death. See if the fan is spinning at all. A lot of them are left running long after the fan stopped spinning.

Another thing to check are the PCIe power leads on the video card. If its not plugged in then it won't display video.


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 Post subject: Re: Mac Pro RAM layout?
PostPosted: Tue Sep 04, 2018 9:24 am 
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Thanks agin MB.

2 Sticks where? 1 & 1 or what? Which slots?


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 Post subject: Re: Mac Pro RAM layout?
PostPosted: Tue Sep 04, 2018 4:30 pm 
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In that chart they list a configuration that's valid for two sticks in a dual CPU configuration.

Attachment:
Capture.GIF
Capture.GIF [ 4.46 KiB | Viewed 311 times ]


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 Post subject: Re: Mac Pro RAM layout?
PostPosted: Tue Sep 04, 2018 4:40 pm 
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Thanks.


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 Post subject: Re: Mac Pro RAM layout?
PostPosted: Sun Sep 09, 2018 1:09 am 
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I have experienced the same issue with the red LED.

I have made a habit of pulling out and reinstalling the processor tray after any Mac Pro has been transported, it seems to make the issue go away.


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 Post subject: Re: Mac Pro RAM layout?
PostPosted: Sun Sep 09, 2018 2:35 am 
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So, the red LED is bad news?


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 Post subject: Re: Mac Pro RAM layout?
PostPosted: Mon Sep 10, 2018 5:38 pm 
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Well, got a new DP->HDMI cable & 2 known good 4 GB sticks of RAM in slpts 1 & 2... it booted... but told me the RM should be in slots 1 & 5 !?

Now I can't get a resolution on the screen that shows the Apple or the Dock! Have tried every resolution, same thing, & with underscan all the way to the right I can blindly get a 1/4inch of the Apple menu to show. :(


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 Post subject: Re: Mac Pro RAM layout?
PostPosted: Tue Sep 11, 2018 11:19 am 
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BDAqua wrote:
Well, got a new DP->HDMI cable & 2 known good 4 GB sticks of RAM in slpts 1 & 2... it booted... but told me the RM should be in slots 1 & 5 !?

Now I can't get a resolution on the screen that shows the Apple or the Dock! Have tried every resolution, same thing, & with underscan all the way to the right I can blindly get a 1/4inch of the Apple menu to show. :(


If the Overscan checkbox is available in the Displays prefpane that should fix that problem immediately.

As for the RAM, by slots 1 and 2, you made sure both sticks are on the first processor tray, correct? I know the original Mac Pro 1,1/2,1 interleaved their RAM on the controller and required you to match pairs of DIMMs in slots 1/5, 2/6, 3/7, 4/8. AFAIK the manuals should be correct for slots 1/2. I don't recall the non-FB DIMM Mac Pros interleaving their RAM.

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 Post subject: Re: Mac Pro RAM layout?
PostPosted: Tue Sep 11, 2018 11:28 am 
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The resolution problems were because the dang TV was set to "Extra Wide" in some obscure setting.

The RAM thing is driving me crazy, after many many combos with 14 sticks, I've seen 3 sticks recognized once, mostly only 2 sticks seen.

Going to try a different RAM sled.


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 Post subject: Re: Mac Pro RAM layout?
PostPosted: Tue Sep 11, 2018 10:37 pm 
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BDAqua wrote:
The resolution problems were because the dang TV was set to "Extra Wide" in some obscure setting.

The RAM thing is driving me crazy, after many many combos with 14 sticks, I've seen 3 sticks recognized once, mostly only 2 sticks seen.

Going to try a different RAM sled.


TV should always be set to 16:9 or its native aspect ratio and in PC Mode. This disables processing on the TV and also kills chroma subsampling to give you proper colors.

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 Post subject: Re: Mac Pro RAM layout?
PostPosted: Wed Sep 12, 2018 12:08 am 
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Thanks, the TV had no such choices, but of course could select input as PC, (VGA), or HDMI.


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 Post subject: Re: Mac Pro RAM layout?
PostPosted: Wed Sep 12, 2018 11:26 am 
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Usually theose are buried in the TV's options menu(s). My (little) Samsung has so many options they broke them into categories.

But at least it booted. The system isn't dead at least.


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 Post subject: Re: Mac Pro RAM layout?
PostPosted: Wed Sep 12, 2018 12:01 pm 
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It is now dead, hit the power button & the only action is the USB mouse lights for couple of seconds. :(


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 Post subject: Re: Mac Pro RAM layout?
PostPosted: Wed Sep 12, 2018 2:28 pm 
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Have you tried calling a witchdoctor? It sounds like the machine may be possessed.


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 Post subject: Re: Mac Pro RAM layout?
PostPosted: Wed Sep 12, 2018 2:36 pm 
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Yes, Witchdoctor is paying for Fed-Ex return. :D


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 Post subject: Re: Mac Pro RAM layout?
PostPosted: Thu Sep 13, 2018 8:53 am 
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Shame I'm not closer to you. I love troubleshooting things to try and make them work. There's a really good possibility that some or all of the RAM had failed due to some catastrophic effect, which if it occurred while situated inside this Mac Pro, could also mean that one or both of the CPU trays was also affected, which would render the machine useless.

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 Post subject: Re: Mac Pro RAM layout?
PostPosted: Thu Sep 13, 2018 9:13 am 
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Thanks ST, I wish we were closer too.


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 Post subject: Re: Mac Pro RAM layout?
PostPosted: Sat Oct 27, 2018 12:58 pm 
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@BD:

My $.02 offering. My MP 5,1 seemed to be "sensitive" to RAM, down to variation in place of manufacture . . . I bought an "8GB" of two 4GB from OWC . . . possibly made in Mex . . . then let's say 8 months later I wanted to get to 16GB, so I order another "8GB" . . . same type, but, that time it was Hecho in China . . . but machine would not accept them, wouldn't boot. Had to send the Chinese RAM back and get a fresh 16 GB . . . all from the current place of manufacture . . . China . . . . Booted up just fine.

e.ep


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 Post subject: Re: Mac Pro RAM layout?
PostPosted: Sat Oct 27, 2018 4:07 pm 
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Thanks eep, it did turn out to be RAM, Mac of all Trades replaced all the RAM & paid for shipping both ways. :)


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 Post subject: Re: Mac Pro RAM layout?
PostPosted: Sat Oct 27, 2018 4:55 pm 
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BDAqua wrote:
Thanks eep, it did turn out to be RAM, Mac of all Trades replaced all the RAM & paid for shipping both ways. :)


Cool. Kind of "interesting" that even if the RAM is the same, whatever, DIMM? same specs . . . the machines won't accept them . . . . sort of has to be all the same batch made in the same factory all at the same time . . . .

I think OWC did provide a return shipping envelope for my second 8 GB . . . sort of reduced the "pain" of it a bit . . . having to buy all 16 GB rather than just another 8 GB . . . . :fishsmack:


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 Post subject: Re: Mac Pro RAM layout?
PostPosted: Sun Oct 28, 2018 1:28 am 
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este.el.paz wrote:
BDAqua wrote:
Thanks eep, it did turn out to be RAM, Mac of all Trades replaced all the RAM & paid for shipping both ways. :)


Cool. Kind of "interesting" that even if the RAM is the same, whatever, DIMM? same specs . . . the machines won't accept them . . . . sort of has to be all the same batch made in the same factory all at the same time . . . .

I think OWC did provide a return shipping envelope for my second 8 GB . . . sort of reduced the "pain" of it a bit . . . having to buy all 16 GB rather than just another 8 GB . . . . :fishsmack:


The reason for this, and you'll see it constantly on the PC side, is because the timings have to match. So if you want 32 GB and you have four slots, you'd need to get a single 8 GB x4 kit as opposed to two 8 GB x2 kits, because the timings would be slightly off on the different kits. This gets even more important if you overclock where every spare cycle needs to be lined up as perfectly as it can be.

It was less of an issue on slower RAM, but the faster RAM gets, the more precisely matched the timings have to be.

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