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mother board and ram amount.

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Old   January 3, 2016, 08:19
Default mother board and ram amount.
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I'm looking into building a new computer to be able to do better 3d work as my current laptop does not support what I need to do.

I was wondering what is the maximum amount of ram that the computer will be able to use to not overspend on resources I don't need.

I was looking into building a system very similar to
http://pcpartpicker.com/b/YDd6Mp.

The basic build is as such
-two(2) e5-2680v3 cpus

either a
https://www.asus.com/us/Motherboards/Z10PED16_WS/ which has 16 ram modules and support up to 1024GB ram
or

https://www.asus.com/us/Motherboards/Z10PED8_WS/ which has 8 ram modules and support up to 512GB ram

-max ram.

I read that on some computer sales sites that the maximum 2 cpus systems can support is 192GB ram and that is amounted to possibly 12x16GB ram.

Here it mentions that
http://ark.intel.com/products/81908/...Cache-2_50-GHz
each cpu can handle up to 68GB.

so 2 CPUs would be 68X2 = 136 GB.

for the
Z10PED16 motherboard,
closest configuration would be
16GB x 8 modules =128 GB
+
2GB X 4 modules =8 GB.
or
16GB x 12 modules =192 GB
+4 free modules

so my questions are
-if the 2 cpu can only use up to 136 GB ram
why can the motherboard support up to 512 and 1024 GB ram. is my analysis wrong?

- what is the best configuration of ram that I should get for the Z10PED16_WS motherboard

- does having extra ram support any other processing or is it wasted?

thanks for your time

Last edited by zero_custom; January 3, 2016 at 10:28.
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Old   January 3, 2016, 09:05
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I dont know which processor you were trying to link (link does not work for me), but all Xeon E5-2xxx v3 including the E5-2680 v3 support 768GB of registered ECC RAM.

For a 2-Socket system get a mainboard with at least 16 DIMM slots for future upgrades.
The proper amount of RAM is entirely up to you. We can not guess how much RAM your computations need. More RAM than actually needed will not speed up anything. However there are a few requirements that allow an initial guess:
With 2 Xeon E5 CPUs you need at least 8 memory modules to get the maximum memory bandwidth possible since each CPU supports quad-channel memory. 16 GB per module are the absolute minimum in my opinion, smaller modules will make future upgrades difficult.
So without any further knowledge about your applications start out with at least 8*16GB of RAM. If you want to start with more RAM, get 8*32GB instead of 16*16GB. But you should really try to estimate the amount of RAM you need before you buy. Avoid unbalanced memory configurations, a multiple of 2 for the amount of DIMMs using only one type of module is the easy and safe way to get maximum performance and stability.
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Old   January 3, 2016, 10:27
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Greetings to all!

Since zero_custom had first sent me the question via PM and I commented in my answer that it would have been preferable to ask in the public forum, I'm glad zero_custom agreed and asked here as well

And since I had sent a complete answer as well, here is the bulk of the answer I wrote to zero_custom via PM:
Quote:
Originally Posted by wyldckat
Quote:
Originally Posted by zero_custom
Here it mentions that
http://ark.intel.com/products/81908/...Cache-2_50-GHz
each cpu can handle up to 68GB.
You misread or there is something wrong with your browser. It's 768GB, not just 68GB .

Quote:
Originally Posted by zero_custom
why can the motherboard support up to 512 and 1024 GB ram. is my analysis wrong?
It's the capacity they tested with. With 8 slots, to achieve 512GB, that means that they tested with modules that have 64GB each. Same goes for 1024GB. Essentially, a module of 64GB is the maximum that is available in the market at the time they built and tested the motherboards, for which they can ensure that things work as intended.
If in 2-6 months modules of 128GB are released, they might be able to test if the motherboards can handle those modules, but until then, they don't know for certain.


Quote:
Originally Posted by zero_custom
- what is the best configuration of ram that I should get for the Z10PED16_WS motherboard
It has 16 slots, 8 per CPU socket. In order to have an optimum use of the processor, you should at least populate 4 slots per socket now and in the future you can populate the other 4 slots. The idea is that since these Xeon processors have 4 communication channels, you make the most of it if you have multiples of 4 slots populated per CPU socket.
To put it in other terms:
  1. You can buy 8 modules of 32GB now, to get 256GB of RAM now.
  2. In the future, you can buy more 8 modules of 32GB, in order to get an addition 256GB of RAM.

Quote:
Originally Posted by zero_custom
- does having extra ram support any other processing or is it wasted?
The operating system will always make use of all of the RAM available for at least storing a cache of the files you're working on. In other words, if you open a file once, the second time it will already be on-RAM and be quicker to open.

Nonetheless, keep in mind that if you're going to install Windows OS, the standard versions can only handle up to 128GB... let me see if I find the link... https://msdn.microsoft.com/en-us/library/windows/desktop/aa366778%28v=vs.85%29.aspx - very curious:
  • Windows 10 Enterprise: 2TB
  • Windows 10 Education: 2TB
  • Windows 10 Pro: 2TB
  • Windows 10 Home: 128GB
Why this limit exists? So that we spend more money on a more expensive Windows version .

Best regards,
Bruno
By the way, an addendum: the OS will use all of the RAM for cache if it's a 64-bit version or if it's 32-bit with PAE support. This to say that standard 32-bit OS' are limited to accessing 4GB of RAM.
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Old   January 3, 2016, 11:05
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Quote:
I dont know which processor you were trying to link (link does not work for me)
thanks Flotus1 I updated the link.

Quote:
Since zero_custom had first sent me the question via PM and I commented in my answer that it would have been preferable to ask in the public forum, I'm glad zero_custom agreed and asked here as well
yes, I'm learning forum etiquette. thanks!

with respect to prices/GB for 32GB sticks are about $11
and 16GB are about $7
and for 64GB its $31.25/GB.

so definitely at this point I will go with you guys recommendation of

32GB X16 = 512GB ram.

so putting things together

ram due to cost limitations: 512GB
CPU:768X2GB = 1536GB ram
Motherboard: 1024 GB ram
windows OS:2 TB

so I was wondering if there is a motherboard that can support 2TB http://www.eteknix.com/intels-new-se...l-cpu-2tb-ram/

for the sake of clarity of understanding, let's say I have scraps of ram sticks in different numbers, can I do this

16 slots

1st cpu
8,8
16,16
16,16
32,32

2nd cpu
8,8
16,16
16,16
16,16

or should i do this.
1st cpu
8,8
8,8
16,16
32,32

2nd cpu
16,16
16,16
16,16
16,16
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Old   January 4, 2016, 16:27
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Always make sure your RAM is balanced between all CPUs and memory channels. This means all channel populated evenly with the exact same RAM. So on your 2 CPU computer you should use either 8 or 16 identical DIMMS.
do not start filling it with old RAM sticks you have lying around.
You could probably do something like this safely, but that's as far as I would push it past everything being identical:
1st cpu
16,8
16,8
16,8
16,8

2nd cpu
16,8
16,8
16,8
16,8



PS: that 68GB/s you read is memory bandwidth, not capacity.
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