AMD vs Intel memory managemement

[James Mcphee]

This is actually a very normal thing to do with memory and is very
reminiscent of the numa architecture.  In this case, you have 2 memory
controllers.  Now, you can use the full bandwidth and only 1 memory
controller at a time, or half the bandwidth but both at the same time.  You
can still reach across to the other memory, but there's a cost.  To put it
simply, the size of our hardware is outrunning our architecture and the
hacks that have allowed large servers to handle this amount of resources is
creeping into our consumer systems.


On Mon, Jun 3, 2013 at 6:36 AM, keith smith <klsmith2020 at yahoo.com> wrote:

>
> I found this in an on-line discussion:
>
> Ganged = dual channel mode for ram. All cores get access to 100% of the
> ram.
>
> unganged = single channel. Each core gets access to a stick of ram.
>
> Is this correct?
>
>
> ------------------------
> Keith Smith
>
> --- On *Mon, 6/3/13, Nathan England <nathan at nmecs.com>* wrote:
>
>
> From: Nathan England <nathan at nmecs.com>
> Subject: Re: AMD vs Intel memory managemement
> To: "Main PLUG discussion list" <plug-discuss at lists.phxlinux.org>
> Date: Monday, June 3, 2013, 1:35 AM
>
>
>
>
>
>
> Yeah, it's a wonderful thing AMD calls "unganged" mode. I have 8 GB of ram
> in my server and the motherboard has enabled "unganged" mode to be more
> efficient. CentOS only recognizes 5.8 GB of ram and I cannot turn off
> unganged mode.
>
>
>
> I love it...
>
>
>
> </sarcasm>
>
>
>
>
> On Sunday, June 02, 2013 17:46:19 keith smith wrote:
>
>
>
>
> Hi,
>
> After that great thread on 32bit vs 64bit, I was wondering if it would be
> beneficial at this point to drill down to the CPU level : AMD vs Intel.
>
> We had a great thread a while ago the AMD CPU, however I do not think that
> thread covered memory management.
>
> I almost went for an AMD CPU this go around (I have a couple from prior
> purchases), however after hearing that AMD does some weird memory
> management at the core level, assigning memory by the bank to each core, I
> thought I would go with an Intel CPU.
>
> If I understand this correctly, It sounds like under some or most
> circumstances the server will lose a portion of the total memory because
> under AMD RAM is assigned at the core level and bank level.  I assume Intel
> uses memory as a pool.  Need memory just grab some until it is gone.
>
> Any thoughts on this?
>
> Thanks!
>
> ------------------------
> Keith Smith
>
>
>
> --
>
>
>
>
>
>
>
> Regards,
>
>
>
> Nathan England
>
>
>
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
> NME Computer Services http://www.nmecs.com
>
> Nathan England (nathan at nmecs.com)
>
> Systems Administration / Web Application Development
>
> Information Security Consulting
>
> (480) 559.9681
>
>
>
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-- 
James McPhee
jmcphe at gmail.com
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