On Thu, 30 Sep 2004 07:38:37 +0800, Winelfred G. Pasamba
<[EMAIL PROTECTED]> wrote:
..
> so, the 3.0ghz CPU is in the "equator", in the north is a 100-166mhz
> bridge to the memory controller which connects at 64bit 400mhz to the
> memory (there can be dual channels in DDR). ganun ba?
>
> which one is 800mhz in the new system boards?
Yes, that's just about right. The memory clock is 100mhz (old) to
166mhz (very new) to even 200mhz i believe. the last, when
quad-pumped, gives your 800mhz "motherboard speed." the reason for the
very conservative memory clock is that, it's very hard to make fast
memory.
> the L1, L2, L3 caches have to be somewhere in between RAM and CPU right?
yes but these are generally internal to the CPU and run at around
4GBytes/second or higher (try memtest86 and see..)
> and in the south of the CPU is the southbridge that runs motherboard
> speed (100-166mhz). on the otherside of the bridge is the 66mhz
> 64-bit PCI. and plugged into our 64-bit PCI is our uw320 scsci that
> says can handle 320Mb/s.
>
> from my understanding of the above if the motherboard which runs at
> 100-166mhz is 64-bit also it will be the bottleneck.
well.. there's the so-called rub. I'm not sure how WIDE the bus is,
from the CPU to the south bridge. it could be wider than 64 bits. also
the south bridge acts as a sort of crossbar interconnect, so it has
more aggregate bandwidth than the individual busses connected to it.
> another thing, what do they mean when they say "400mhz system bus" in
> the old RDRAM motherboards?
100mhz system bus, quad-pumped. what is "quad pumped?"
in "double-pumped" or DDR, the memory is clocked at the rising and
falling edge of a 100mhz clock, giving effective 200mhz clock.
if you have 2 clock signals, 180* out of phase ("biphase clock") and
you clock 2 memory modules off the 2 different clocks, you get a
different kind of DDR (actually it's interleaving). if you have a
biphase clock, that is ALSO triggered on the rising edge and falling
edge of the clock signal, then you have quad-pumped. all Pentium-IV's
are quad-pumped (the RDRAM ones at least).
> are there any other bridges, busses, etc, that affect database performance?
nope. just PCI or PCI-X bus speed.
> btw, anyone here has tried if the Asus deluxe motherboard in pcxpress
> can really handle more than 3gigs? and has someone tested its
> compatibility with adaptec uw320 64-bit scsi controller(s)?
i have the asus Deluxe, but only with 2GB ram. i don't think it's an
issue, the Asus Deluxe doesn't bring out the Xeon PAE bit (it's a
WORKSTATION motherboard), so 4GB ram is the maximum -- not far from
the 3GB figure you have. you can get up to 16GB RAM using the PAE bit,
but the motherboard also has to support it. only really high-end
(read: not available at the retail store) motherboards bother to
support PAE.
N.B. the athlon XP also implements the PAE bit. but i dare you to find
any athlon motherboard (not counting opterons which are 64bit anyway
and don't need PAE) which implements it.
--
Philippine Linux Users' Group (PLUG) Mailing List
[EMAIL PROTECTED] (#PLUG @ irc.free.net.ph)
Official Website: http://plug.linux.org.ph
Searchable Archives: http://marc.free.net.ph
.
To leave, go to http://lists.q-linux.com/mailman/listinfo/plug
.
Are you a Linux newbie? To join the newbie list, go to
http://lists.q-linux.com/mailman/listinfo/ph-linux-newbie
