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Confirmation of Westmere Memory Config

mattmower said:
A small amount of extra information, I emailed Crucial in the UK about their 8GB part and whether they had tested on pre-release units and they responded:

>Thanks for your email. I can confirm that the 2010 6 Core Mac Pro will
>support 8GB per slot for a 32GB capacity. We have indeed tested the 8GB
>modules to work on pre release units of this model and we guarantee them
>to be compatible.

Matt
Click to expand...

That's good news... what would 3x8GB cost? :eek:
 
I'm really confused.

I would love to put 3x8gb or 4x8gb sticks in.

I wonder when we will get a definitive answer.
 
We will know when one of us puts them in and tries it. 3 makes more sense than 4 because it would stay in the base triple channel mode per the design of the board. I hope to test some of these late next week.
 
3 x 8 GB I can believe working.

But I doubt 32 GB worked. The CPU's specs say its limit is 24. Maybe the system recognized 32 being installed, but couldn't actually use it all?
 
eponym said:
3 x 8 GB I can believe working.

But I doubt 32 GB worked. The CPU's specs say its limit is 24. Maybe the system recognized 32 being installed, but couldn't actually use it all?
Click to expand...

From a CPU perspective this makes no sense to me.

It's the same chip in the dual CPU model and the memory isn't partitioned with each CPU only seeing 24MB.

M.
 
It's not the same CPU in the dual.

The 3.33 6-core W3680 can't be used in a dual config.

The specs themselves say:

Max Memory Size
(dependent on memory type): 24 GB

^ the vague part is "memory type". We don't know what that really means.
 
eponym said:
It's not the same CPU in the dual.

The 3.33 6-core W3680 can't be used in a dual config.

The specs themselves say:

Max Memory Size
(dependent on memory type): 24 GB

^ the vague part is "memory type". We don't know what that really means.
Click to expand...

Ah yes, that was sloppy of me. The W3680 with 24GB vs the X5660 with its, rather enviable, 288GB memory limit! That's quite a steep drop off.

W
 
I'm praying for 3x8 working. 12GB won't cut it for long.
 
I think you lot are getting all over yourselfs for no reason at all.

The chipset is the same as the 2009 MP, all has changed are the CPUs slotted into it.

Im 99% confident that 3 slots vs 4 slots will still yield the best memory bandwidth.

We shall see when barefeats/other places get the 2010 MP.
 
Concorde Rules said:
...

Im 99% confident that 3 slots vs 4 slots will still yield the best memory bandwidth.
Click to expand...

I think there's no doubt about that. But in no way does that mean that everyone should conclude that 3 sticks are better than 4 in their own case.

Let's say that populating the 4th slot reduces the bandwidth by around 25% because it drops from 3-way to 2-way interleave when your main-memory subsystem is running flat-out. So?

How often is your memory subsystem running flat out, given the unique, new, and relatively enormous cache system of the Nehalem/Westmere architecture? How much is that drop reflected in your real overall system performance? How much is it offset in your particular system by having an extra 4GB of RAM? I assure you that for every synthetic benchmark you can come up with showing a slowdown of something that basically never happens in practice (your super-high-speed memory system getting saturated), Kingston and Crucial can come up with 5 more showing that the extra 4GB in the fourth slot improves your performance on XYZ applications even though it cuts down your interleave factor.

It is true that your maxed out memory scenario runs best with a multiple of 3. And IF it is also true that you're fine with 12GB instead of 16 with a single CPU, then maybe you should only populate 3, that's what I'm doing.

But, the more I read about this stuff (give this a long slow glance if you want some detail), the more I realize what the truth is:

For 99.98% of users the 3-sticks vs. 4 sticks controversy simply doesn't matter in real-life practice. It's a non-issue that's easy to mistake for an issue. 'Do what thou wilt' shall be the whole of the law. If you want 3, get 3. If you want 4, get 4. Ignore the many over-hyped benchmarks aimed at arousing the paranoia wired into our lizard brains. The difference is a few percent either way in real life situations on the memory access, and you'll be helped by more memory more often than you'll be hurt by less interleave.

Bottom line: we are indeed getting all over ourselves for no reason at all. The right thing to do: forget the whole issue.

EDIT: Nothing about the above mitigates the indisputable fact that it's kind of a shame to design a motherboard for these CPU's that has anything other than a multiple of 3 memory sockets.
 
trankdart said:
I think there's no doubt about that. But in no way does that mean that everyone should conclude that 3 sticks are better than 4 in their own case.

Let's say that populating the 4th slot reduces the bandwidth by around 25% because it drops from 3-way to 2-way interleave when your main-memory subsystem is running flat-out. So?

How often is your memory subsystem running flat out, given the unique, new, and relatively enormous cache system of the Nehalem/Westmere architecture? How much is that drop reflected in your real overall system performance? How much is it offset in your particular system by having an extra 4GB of RAM? I assure you that for every synthetic benchmark you can come up with showing a slowdown of something that basically never happens in practice (your super-high-speed memory system getting saturated), Kingston and Crucial can come up with 5 more showing that the extra 4GB in the fourth slot improves your performance on XYZ applications even though it cuts down your interleave factor.

It is true that your maxed out memory scenario runs best with a multiple of 3. And if it is also true that you're fine with 12GB instead of 16 with a single CPU, then maybe you should only populate 3, that's what I'm doing.

But the truth is, the more I read about this stuff (give this a long slow glance if you want some detail), the more I settle on what the truth is:

For 99.98% of users the 3-sticks vs. 4 sticks controversy simply doesn't matter in real-life practice. It's a non-issue that's easy to mistake for an issue. 'Do what thou wilt' shall be the whole of the law. If you want 3, get 3. If you want 4, get 4. Ignore the many over-hyped benchmarks aimed at arousing the paranoia wired into our lizard brains. The difference is a few percent either way in real life situations on the memory access, and you'll be helped by more memory more often than you'll be hurt by less interleave.

Bottom line: we are indeed getting all over ourselves for no reason at all. The right thing to do: forget the whole issue.
Click to expand...

Absolutely (I didn't include the real-life results of 4 vs 3 sticks)

I personally went for 6Gb however my 2011 Mac Pro (Sandy Bridge) will have 12Gb minimum :D
 
trankdart said:
I think there's no doubt about that. But in no way does that mean that everyone should conclude that 3 sticks are better than 4 in their own case.

Let's say that populating the 4th slot reduces the bandwidth by around 25% because it drops from 3-way to 2-way interleave when your main-memory subsystem is running flat-out. So?

How often is your memory subsystem running flat out, given the unique, new, and relatively enormous cache system of the Nehalem/Westmere architecture? How much is that drop reflected in your real overall system performance? How much is it offset in your particular system by having an extra 4GB of RAM? I assure you that for every synthetic benchmark you can come up with showing a slowdown of something that basically never happens in practice (your super-high-speed memory system getting saturated), Kingston and Crucial can come up with 5 more showing that the extra 4GB in the fourth slot improves your performance on XYZ applications even though it cuts down your interleave factor.

It is true that your maxed out memory scenario runs best with a multiple of 3. And IF it is also true that you're fine with 12GB instead of 16 with a single CPU, then maybe you should only populate 3, that's what I'm doing.

But, the more I read about this stuff (give this a long slow glance if you want some detail), the more I realize what the truth is:

For 99.98% of users the 3-sticks vs. 4 sticks controversy simply doesn't matter in real-life practice. It's a non-issue that's easy to mistake for an issue. 'Do what thou wilt' shall be the whole of the law. If you want 3, get 3. If you want 4, get 4. Ignore the many over-hyped benchmarks aimed at arousing the paranoia wired into our lizard brains. The difference is a few percent either way in real life situations on the memory access, and you'll be helped by more memory more often than you'll be hurt by less interleave.

Bottom line: we are indeed getting all over ourselves for no reason at all. The right thing to do: forget the whole issue.

EDIT: Nothing about the above mitigates the indisputable fact that it's kind of a shame to design a motherboard for these CPU's that has anything other than a multiple of 3 memory sockets.
Click to expand...

Well put sir.
 
trankdart said:
I think there's no doubt about that. But in no way does that mean that everyone should conclude that 3 sticks are better than 4 in their own case.

Let's say that populating the 4th slot reduces the bandwidth by around 25% because it drops from 3-way to 2-way interleave when your main-memory subsystem is running flat-out. So?

How often is your memory subsystem running flat out, given the unique, new, and relatively enormous cache system of the Nehalem/Westmere architecture? How much is that drop reflected in your real overall system performance? How much is it offset in your particular system by having an extra 4GB of RAM? I assure you that for every synthetic benchmark you can come up with showing a slowdown of something that basically never happens in practice (your super-high-speed memory system getting saturated), Kingston and Crucial can come up with 5 more showing that the extra 4GB in the fourth slot improves your performance on XYZ applications even though it cuts down your interleave factor.

It is true that your maxed out memory scenario runs best with a multiple of 3. And IF it is also true that you're fine with 12GB instead of 16 with a single CPU, then maybe you should only populate 3, that's what I'm doing.

But, the more I read about this stuff (give this a long slow glance if you want some detail), the more I realize what the truth is:

For 99.98% of users the 3-sticks vs. 4 sticks controversy simply doesn't matter in real-life practice. It's a non-issue that's easy to mistake for an issue. 'Do what thou wilt' shall be the whole of the law. If you want 3, get 3. If you want 4, get 4. Ignore the many over-hyped benchmarks aimed at arousing the paranoia wired into our lizard brains. The difference is a few percent either way in real life situations on the memory access, and you'll be helped by more memory more often than you'll be hurt by less interleave.

Bottom line: we are indeed getting all over ourselves for no reason at all. The right thing to do: forget the whole issue.

EDIT: Nothing about the above mitigates the indisputable fact that it's kind of a shame to design a motherboard for these CPU's that has anything other than a multiple of 3 memory sockets.
Click to expand...

Exactly!... put simply: Configure your memory for quantity first and speed second... Having enough memory is more important than faster memory. :)
 
I agree with "trankdart." This is what I learned on the 2009 Nehalem in my testing as recent as yesterday:

1. Though DLT stress test showed the 8-core Nehalem with 6 memory modules having much higher bandwidth than with 8 memory modules, when I ran the bandwidth test so that you only use the first 12G of the 16G config, the bandwidth is the same for both memory configs.

2. Real world apps (currently) don't saturate the memory bandwidth so it does not make a difference in the real world. I can back that up with test data showing the Nehalem with 16GB of RAM equaling or beating the time it took the 12GB config to complete After Effects CS5 renders, Compressor 3.5 renders, Photoshop CS5 action files, etc.

3. In the AE CS5 render, 14G of the 16GB of memory was in use -- which brings me to my third point. It's more often better to have sufficient memory than to have the perfect theoretical memory config.
 
Assuming the 6-core Westmere handles 8G modules from Crucial (or whomever), with the 24G limit and dual channel design, seems to me the best way to achieve 24G is to install 2x8G + 2x4G = 24G.
 
barefeats said:
Assuming the 6-core Westmere handles 8G modules from Crucial (or whomever), with the 24G limit and dual channel design, seems to me the best way to achieve 24G is to install 2x8G + 2x4G = 24G.
Click to expand...

They recommend using the exact same sizes and throughout.
 
xgman said:
They recommend using the exact same sizes and throughout.
Click to expand...

I've just thought what about this setup:

Channel 1 - 2x 4Gb
Channel 2 - 8Gb
Channel 3 - 8Gb

Then the addressable space is the same for each channel and in theory could possibly allow three channel operation at max speed?

Although I suspect the lack of ability to address either of the 4Gb sticks at the same time might block that idea. :(
 
I doesn't work that way. And you can't mix 8GB modules with other sizes.

If you go with 8GB DIMMs, you can only use 8GB DIMMs.
 
Very interesting board layout from a 3.33 6 core box just received by one of our members regarding the 4 slots:

"Yes -- they are all black "
"The originally installed 3 x 1 GB chips were installed in the forward 3 slots (towards the open side) so it is a good guess that those are the tri-channel slots."

I would have expected a triple channel design like the Intel WX58BP to have one a different color. probably means nothing, but still odd.

https://forums.macrumors.com/showthread.php?p=10875147&posted=1#post10875147

http://att.macrumors.com/attachment.php?attachmentid=247203&d=1282232023

also read page 49 of the manual":
http://manuals.info.apple.com/en_US/Mac_Pro_Mid2010_UG_5686.pdf

and Intel spec:
http://www.intel.com/support/motherb...965.htm#triple

and see page 35 of this MB manual which is the only Intel retail board to support this cpu:
http://download.intel.com/support/m...58bp/sb/e69058001_wx58bp_productguide_001.pdf
 
The 2010 manual says if you don't populate the slots to provide optimum performance, a "Memory Slot Utility" appears on the screen and recommends a better configuration.
 
xgman said:
They recommend using the exact same sizes and throughout.
Click to expand...

Who recommends that? I checked the manual you linked to, and I don't seem to read anywhere that equal sized DIMMs are recommended?

eponym said:
I doesn't work that way. And you can't mix 8GB modules with other sizes.

If you go with 8GB DIMMs, you can only use 8GB DIMMs.
Click to expand...

According to the manual, page 49, it's possible.
 
eponym said:
I doesn't work that way. And you can't mix 8GB modules with other sizes.

If you go with 8GB DIMMs, you can only use 8GB DIMMs.
Click to expand...

Could two 4Gb sticks and two 2Gb sticks work in tri-channel still?

Want to add a few more Gb to my Mac Pro 2009.
 
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