I decided to upgrade my ram from 7GB to 11Gb by adding 2x 2GB sticks. So before the upgrade I had:

2x 2GB
2x 1GB
2x 512MB

I bought my Ram @ Canada RAM sells memory in Canada - Apple Mac Pro Penryn 4-Core and 8-Core, Dual intel Xeon, Quad Workstation (http://www.canadaram.com/apple_mac_pro.htm) and they're instructions was to add configure it from Largest to lowest:

So I had it setup:

Riser A Slot 1 - 2GB
Riser A Slot 2 - 2GB

Riser B Slot 1 - 2GB
Riser B Slot 2 - 2GB

Riser A Slot 3 - 1GB
Riser A Slot 4 - 1GB

Riser B Slot 3 - 512MB
Riser B Slot 4 - 512MB

Now the problem I had with this is that every time my computer would wake up from sleep, my fans would go nuts for about 15 seconds and run to 2500-3000 RPM's. My idle speeds were at 1100-1300.

I tried everything from reseting SMC, PRAM cleaning out caches, and re installing the combo updater until I finally just decided to take the ram out. Idle's went back to 500 RPMS, and no problems.

Now I have it configured it :


So my Ram looked like this:
Riser A Slot 1 - 2GB
Riser A Slot 2 - 2GB

Riser B Slot 1 - 1GB
Riser B Slot 2 - 1GB

Riser A Slot 3 - 512MB
Riser A Slot 4 - 512MB

Riser B Slot 3 - 2GB
Riser B Slot 4 - 2GB

And my fan speeds seems to be just right, idling around 500. Temps are a bit higher (30C to about 35-40C, so I just bump up my fans using SMC Fan Control.

I know I've seen lots of threads where there is too much dust build inside and can cause this, but I've already done this with no success and checked to see if my heatsink sensors were plugged in.

Anyways, sorry for the long story here, but can anyone tell me the correct configuring my RAM? And can anyone explain why my fans would go nuts when the CPU temps are just normal?

This should work for you:

Riser A Slot 1 - 2GB
Riser A Slot 2 - 2GB
Riser A Slot 3 - 2GB
Riser A Slot 4 - 2GB

Riser B Slot 1 - 1GB
Riser B Slot 2 - 1GB
Riser B Slot 3 - 512MB
Riser B Slot 4 - 512MB

This is exactly how my RAM is configured.

Or it could be your new RAM is DOA or of the wrong type.

Sorry no idea re:why your fans keep going.

I found this guide to help with configurations for best performance I guess which tries to make matched pairs on the 1&2 slots on A and B - which takes advantage of a 256-bit wide memory architecture.

That being said, Ill try your way screature and put all the 2GB on A.

http://homepage.mac.com/tribe3/.pictures/MemConfig.jpg

So i just tried to put all the 2gbs on Card A. From sleep my fans do ramp, but only to about 1700 RPMS.

Maybe configuring it to 256 wide on and trying to balance a & b will trigger something to make sure all the built up heat from sleep is forced out?

I do have the correct ram PC 2 5300 ECC FB 667

The guide is correct, the fastest configuration is to have all 4 of the 2 GB modules in the 1 and 2 slots == A1 A2 B1 B2
The 3 and 4 sockets are slower than the 1 and 2 sockets.
We are suspecting a problem with the heatsink on one of the new modules, we're shipping replacements, so don't sweat this any harder until you get your new modules to try.

The guide is correct, the fastest configuration is to have all 4 of the 2 GB modules in the 1 and 2 slots == A1 A2 B1 B2
The 3 and 4 sockets are slower than the 1 and 2 sockets.
We are suspecting a problem with the heatsink on one of the new modules, we're shipping replacements, so don't sweat this any harder until you get your new modules to try.

Thanks! I did get your email, and thanks for taking care of me here!

So i just tried to put all the 2gbs on Card A. From sleep my fans do ramp, but only to about 1700 RPMS.

Maybe configuring it to 256 wide on and trying to balance a & b will trigger something to make sure all the built up heat from sleep is forced out?

I do have the correct ram PC 2 5300 ECC FB 667

Ramping of your fans from sleep is normal in my experience...

I tried installing the RAM in the recommend 256bit manner you describe and I was never able to have all the RAM showing in system profiler, putting all 4x2GB modules on the same card was the only way I was able to get all the RAM to show up... I can't explain it but I just had to go with what worked for me.

Yep you definitely have the correct RAM.

Ramping of your fans from sleep is normal in my experience...

I tried installing the RAM in the recommend 256bit manner you describe and I was never able to have all the RAM showing in system profiler, putting all 4x2GB modules on the same card was the only way I was able to get all the RAM to show up... I can't explain it but I just had to go with what worked for me.

Yep you definitely have the correct RAM.

Do you have the 8 core 5365's in your 1,1?

How fast would fans start to run @? Mine kind of acts like that sometimes but is specific to the Apple 1GB sticks. Sometimes it would not be detected and the red light on the daughter board would come on. I just down pull the card out and then back in and it seems to work for me after the restart.

The guide is correct, the fastest configuration is to have all 4 of the 2 GB modules in the 1 and 2 slots == A1 A2 B1 B2
The 3 and 4 sockets are slower than the 1 and 2 sockets.
We are suspecting a problem with the heatsink on one of the new modules, we're shipping replacements, so don't sweat this any harder until you get your new modules to try.

Any idea why if I install my RAM in that configuration it comes up 4GB short and when I put all 4x 2GB in the top riser the system profiler show all 11GB? I got the same sheet from you when I upgraded to 11GB, I did the same thing as mlke.

Do you have the 8 core 5365's in your 1,1?

How fast would fans start to run @? Mine kind of acts like that sometimes but is specific to the Apple 1GB sticks. Sometimes it would not be detected and the red light on the daughter board would come on. I just down pull the card out and then back in and it seems to work for me after the restart.

No I have dual Xeon 5160s (dual 3.0 GHz) for quad core.

I've had no issues with my macpro1,1 when waking from a sleep with the ram configuration suggested by Apple.

My configuration:
Riser A Slot 1 - 4GB
Riser A Slot 2 - 4GB
Riser A Slot 3 - 2GB
Riser A Slot 4 - 2GB

Riser B Slot 1 - 4GB
Riser B Slot 2 - 4GB
Riser B Slot 3 - 512MB
Riser B Slot 4 - 512MB

Thumbs up to CanadaRAM's service though.

Any idea why if I install my RAM in that configuration it comes up 4GB short and when I put all 4x 2GB in the top riser the system profiler show all 11GB? I got the same sheet from you when I upgraded to 11GB, I did the same thing as mlke.

It may be an issue with the riser card itself. It would be interesting to exchange the position of the two riser cards, and then repeat the test.

The other thing that can't be ruled out is a mismatch between two brands of RAM, if they are installed in the same Quad channel bank (A1 A2 B1 B2). When you put them into A1 A2 A3 A4 they are in different banks. Are all of the 2 GB modules the same brand and model? To match, Apple says they have to be the same "speed, size and configuration" but then they don't say what aspects of configuration are significant.

i've always found mac pro's to be extremely picky in RAM configurations.

It may be an issue with the riser card itself. It would be interesting to exchange the position of the two riser cards, and then repeat the test.

The other thing that can't be ruled out is a mismatch between two brands of RAM, if they are installed in the same Quad channel bank (A1 A2 B1 B2). When you put them into A1 A2 A3 A4 they are in different banks. Are all of the 2 GB modules the same brand and model? To match, Apple says they have to be the same "speed, size and configuration" but then they don't say what aspects of configuration are significant.

Thanks for the feedback... I will try as you suggest and report back when I have a chance.

@screature - since you also have 11GB of ram, at what speeds does your fan speed up to when waking up?

Question: which has the bigger expected speedup: 1- putting the largest RAM modules in slots 1&2, or 2- having 4 matched pairs to trigger the quad-access?

I have 4 1G modules and 2 4G modules. I put the 1G modules in slots 1&2 of both risers to get the 256-bit accesses, and the 2 4G modules in slots 3&4 of riser A. This seems to go against the logic of the diagram posted here which seems to push for having the larger modules in slots 1&2 even if there is only one pair (see the "C" column of upgrades).

@screature - since you also have 11GB of ram, at what speeds does your fan speed up to when waking up?

I really don't know as I don't use a utility to tell me, but when I woke up my MP today when coming home it didn't seem to cause the fan to ramp up as much as I seemed to think it does, just a little audible difference, nothing significant, not like starting up... at this point I think it is probably best just to wait to see what Canada RAM provides to rectify the situation...

BTW I didn't get a chance to pull my RAM and reconfigure it as it was a busy night, I will see if I have time tomorrow.

:clap: @Canada RAM - looks like the replacement modules fixed my problem.

I never knew that the heatsinks being loose would of been the issue as they don't look loose at all.

Anyways, thanks again for taking care of this asap and paying for shipping both ways. I'll always recommend you guys for Apple parts!

Question: which has the bigger expected speedup: 1- putting the largest RAM modules in slots 1&2, or 2- having 4 matched pairs to trigger the quad-access?

I have 4 1G modules and 2 4G modules. I put the 1G modules in slots 1&2 of both risers to get the 256-bit accesses, and the 2 4G modules in slots 3&4 of riser A. This seems to go against the logic of the diagram posted here which seems to push for having the larger modules in slots 1&2 even if there is only one pair (see the "C" column of upgrades).

Just wanted to bump this question in case I move on to 4GB modules... How should this be configured? 8GB on Riser A and the 4x 1GB on Riser B ?

In general we recommend going from largest to smallest A1A2 B1B2 A3A4 B3B4

The explanation is a little long-winded, but bear with me.

There is a theoretical loss of memory bandwidth if you split up a matching quad-channel (A1A2 B1B2) foursome (but it is a marginal difference in real life)

The reason that we recommend the largest to smallest configuration is to put the largest amount of memory into the 1 and 2 sockets. With the MacPro Fully Buffered memory design, the motherboard's memory controller does not access the 3 and 4 slots directly. The memory can run faster and the motherboard can be manufactured more cheaply if the FB-DIMM's onboard controller handles some of the logic.

So instead of addressing the Slot 3 and 4 RAM directly, the motherboard memory controller makes all requests to the FB-DIMMs in the 1 and 2 RAM slots; the FB controller chip on the module itself decides whether the request is for memory resident on its module (lets say slot 1) or whether it is actually addressing memory on slot 3. In the second case, it passes the request to the FB DIMM in slot 3 for filling. This introduces a small latency to the transaction, plus it makes the chip work harder and generate more heat. This is one reason why Apple specifies the big mother heatsinks on the RAM, the FB-DIMMs run a lot hotter than normal DDR2.

So our recommendation is to minimize the number of requests to the 3 and 4 slots by putting the majority of the RAM in the 1 and 2 slots. I would go as far as to say if you have 9 GB or more of RAM and are running the original Apple 512 MB FB-DIMMs in your 3 and 4 sockets, consider taking them out. You'll lose 1 GB of RAM, but you will reduce heat and memory latency.

Having said all that, if you have particular set of chips that run well for you in a 1-2-3-4 configuration, it is safe to leave them there.