Re: FreeBSD is very slow when Memory chip sizes are imbalanced in slots

On Mon, Mar 18, 2013 at 2:28 PM, olli hauer <ohauer_at_gmx.de> wrote:

> On 2013-03-18 21:43, Mehmet Erol Sanliturk wrote:
> > On Mon, Mar 18, 2013 at 9:48 AM, Scot Hetzel <swhetzel_at_gmail.com> wrote:
> >
> >> On Mon, Mar 18, 2013 at 11:06 AM, Mehmet Erol Sanliturk
> >> <m.e.sanliturk_at_gmail.com> wrote:
> >>> Computer A : Memory Chip Sizes : ( 2 GB , 1 GB , 2 GB , 1 GB ) :
> Working
> >>> SLOW . FreeBSD A
> >>> Computer B  : Memory Chip Sizes : ( 2 GB , 2 GB , 2 GB , 2 GB ) :
> Working
> >>> FAST . FreeBSD B
> >>>
> >>> Interchange memory chips :
> >>>
> >>> Computer A : Memory Chip Sizes : ( 2 GB , 2 GB , 2 GB , 2 GB ) :
> Working
> >>> FAST . FreeBSD A
> >>> Computer B  : Memory Chip Sizes : ( 2 GB , 1 GB , 2 GB , 1 GB ) :
> Working
> >>> SLOW . FreeBSD B
> >>>
> >>>
> >>
> >> What happens if you configure the memory as ( 2 GB , 2 GB , 1 GB , 1 GB
> )?
> >>
> >> --
> >> DISCLAIMER:
> >>
> >> No electrons were maimed while sending this message. Only slightly
> bruised.
> >>
> >
> >
> > This can NOT be done  , because
> >
> > Channel A : Slot 1 :
> >                    Slot 2 :
> >
> > Channel B : Slot 1 :
> >                    Slot 2 :
> >
> > ( Slot 1 , Slot 1 ) should be equivalent when chips inserted to both .
> > ( Slot 2 , Slot 2 ) should be equivalent when chips inserted to both .
> >
> > Thank you ver much .
> >
>
> I suspect the BIOS does not detect the optimal timing for the "SLOW" RAM or
> a RAM Module is running on a slower timing.
>
> What happen if you test with only the 2GB or the 1GB modules (to identify
> possible CHIP issues).
> How is the memory detected in the BIOS (timings ...) some newer BIOS can
> run manual tests to detect timing issues.
>
>
>
>
These are worked :

http://lists.freebsd.org/pipermail/freebsd-current/2012-February/031836.html
http://lists.freebsd.org/pipermail/freebsd-current/2012-February/031912.html
http://lists.freebsd.org/pipermail/freebsd-current/2012-February/031928.html
http://lists.freebsd.org/pipermail/freebsd-current/2012-February/032012.html


It seems that memory chip sizes are not checked one by one or used per chip
in slots , but a COMMON value is used :

Size of chip in first slot . When size of chip in second slot is smaller
than size of chip in first slot , problem appears .

Thank you very much .

Mehmet Erol Sanliturk