Date: Mon, 18 Mar 2013 03:30:40 -0700 From: Mehmet Erol Sanliturk <m.e.sanliturk@gmail.com> To: Tom Evans <tevans.uk@googlemail.com> Cc: freebsd-current <freebsd-current@freebsd.org> Subject: Re: FreeBSD is very slow when Memory chip sizes are imbalanced in slots Message-ID: <CAOgwaMtTmx4LhEdrg3WNjZA-uyTRSN913RBWrrqMia4GZhP_zA@mail.gmail.com> In-Reply-To: <CAFHbX1LcCGoWy%2BHzp8T7z4noFZAMK1-sCuWpO_Z_ybhnoMMY5A@mail.gmail.com> References: <CAOgwaMss0cB9bFqCkjzukb-=9FqgLN9vthL5QdQsk-6Lknk5VQ@mail.gmail.com> <CAFHbX1LcCGoWy%2BHzp8T7z4noFZAMK1-sCuWpO_Z_ybhnoMMY5A@mail.gmail.com>
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On Mon, Mar 18, 2013 at 3:01 AM, Tom Evans <tevans.uk@googlemail.com> wrote: > On Sun, Mar 17, 2013 at 8:26 PM, Mehmet Erol Sanliturk > <m.e.sanliturk@gmail.com> wrote: > > Dear All , > > > > Previously , in the following message , I have mentioned effect of memory > > chip placement on execution speed : > > > > > http://lists.freebsd.org/pipermail/freebsd-current/2012-February/031836.html > > Effect of Processor and Memory on KDE4 execution > > speed< > http://lists.freebsd.org/pipermail/freebsd-current/2012-February/031836.html > > > > These seems to be more than different memory slot allocation between > those two boxes. > > Can you reproduce this on the one labelled 'FAST' by assigning memory > in the same manner as it is assigned in the one labelled 'SLOW'? > > > > > > > The above thread did not produce any usable result . > > > > The problem is persisting over 9.1 and 10.0 current . > > > > My opinion is that , it is NOT related to KDE only . > > > > After X is started , any desktop is behaving very slowly . > > This is also visible in PC-BSD and GhostBSD . > > This is very nebulous. What is 'very slowly'? Is there a test you can > run that is independent of X, KDE, etc that demonstrates this? > > One thing that KDE does require (iirc - from about 5 years ago, > probably wrong now) is that since KDE is C++, it spends a lot of time > loading executables/libraries into memory and prelinking them. If you > have dramatically lowered your RAM bandwidth, then this stage could > take a lot longer. > > One thing that could cause memory bandwidth to lower is by installing > mismatched modules. The BIOS will set all RAM up at the same speed, > the lowest that all of the installed RAM supports. If you fill the RAM > slots with mismatched modules of different sizes, it may also not > enable dual channel memory, further reducing the RAM bandwidth. > > Because of this, I think it is a jump to go from "My computer runs > slow when I put these bits of RAM in" to "FreeBSD always runs slow > when there is mismatched RAM". > > If you find out what is slow on FreeBSD - eg RAM bandwidth - you can > then test the same thing in Linux. If Linux shows the same slowdown > from fast to slow, then I'm sorry, that's a hardware defect. If, on > the other hand, Linux is just as fast in both configurations, then I'm > sure a lot of people would be interested as to why. > > Cheers > > Tom > I think , all of the answers to your questions may be found in the above referenced thread messages : Every possible combination has been tried , and identified that the problem is different memory chip sizes for FreeBSD ( v9.0 , v9.1 , v10.0 ) ( GhostBSD , PC-BSD , v9.0 , v9.1 ) : Channel A : Slot 1 : 2 GB Slot 2 : 1 GB Channel B : Slot 1 : 2 GB Slot 2 : 1 GB All of the memory chips : Kingston HyperX , same clock frequency . Memory placement kind is correct . There is NO any hardware defect . Linux is insensitive to such different memory chip sizes ( I am using Fedora , CentOS , Mandriva , Mageia , OpenSUSE , Arch Linux , Puppy Linux , and some others ... ) Thank you very much . Mehmet Erol Sanliturk
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