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Q: FSB and Memory ( Answered 5 out of 5 stars,   3 Comments )
Subject: FSB and Memory
Category: Computers > Hardware
Asked by: leonchik-ga
List Price: $4.00
Posted: 25 Aug 2006 08:38 PDT
Expires: 24 Sep 2006 08:38 PDT
Question ID: 759450
This is configuraion of my new computer:
Motherboard - Intel DG965WH, 
Processor - Intel Conroe Core 2 Duo E6600 2.4GHz 4MB
Memory - Corsair 2GB (1GB*2) DDR-2 667
With this configuration, will 667 memory slow CPU work? 1066-Mhz
system bus? or I need 800 Mhz memory to get best results (i mean FSB)
With this memory will i get 1066-Mhz system bus?
Subject: Re: FSB and Memory
Answered By: keystroke-ga on 25 Aug 2006 10:15 PDT
Rated:5 out of 5 stars
After some research into your question I have found that the following
memory by corsair has been confirmed to work at 1066 MHZ FSB

Corsair XMS2-8500

The product can be found directly here.

To purchase this memory directly you can buy it from here

The following review tells you more about the memory performance,
including giving you benchmark of the memory running at 1066 mhz
compared to other memory running at slower speeds. This review uses
the 965 chipset exactly as you have along with a Duo Core 2 Intel CPU.

You may find this article intersting too.

I do not believe that the corsair 667 memory will run at 1066 mhz
without overclocking the memory (pushing it beyond its designed means)
and increasing the cooling inside the PC (if you do not apply extra
cooling the machine will overheat and this will hurt the motherboard,
memory and CPU). You are best off purchasing the 1066 mhz memory
rather than trying to push 667 memory to the higher speeds.

So to answer your question, by default your memory will run at 667
unless you overwrite the setting within the motherboard's BIOS and
explicitly push the memory (and FSB) to 1066. I personally would not
advise this (as I did it before and left the machine at this speed and
slowly ruined it) unless you are experienced with PC hardware and
cooling systems.

My advice would be to buy the 1066 mhz memory and have the machine
running at a stock level of 1066 all round without any overclocking
involved. This is much safer.


Request for Answer Clarification by leonchik-ga on 25 Aug 2006 10:28 PDT
so what FSB will i get with 667 ??? this motherboard allows only 1066/800/533..

Request for Answer Clarification by leonchik-ga on 25 Aug 2006 10:35 PDT
I haven't found if this motherboard supports 1066 memory

Request for Answer Clarification by leonchik-ga on 25 Aug 2006 11:24 PDT
according documentation of this specific motherboard, maximum
supported memory is 800

Clarification of Answer by keystroke-ga on 25 Aug 2006 12:28 PDT
You are correct that this motherboard does not natively support 1066 MHZ memory.

The motherboard does support a CPU that can take a 1066 MHZ FSB but as
the motherboard is only capable of 800MHZ you will be limited to this
speed as default (dependent upon any overclocking measures available).

If you would like 800MHZ memory you would be best off ordering

These can be purchased here

Sometimes motherboard manufacturers release BIOS updates that allow
you to further extend the speeds of the motherboard and the FSB
however I would never rely on this information as a basis for making
my purchasing decisions.

If you were to buy 667 MHZ memory you would be able to run at a 667
MHZ FSB because the motherboard DOES support 667MHZ FSB.

	Four 240-pin DDR2 SDRAM Dual Inline Memory Module (DIMM) sockets
	Support for DDR2 800, DDR2 667, or DDR2 533 MHz DIMMs
	Support for up to 8 GB of system memory"

I would advise you to obtain the 800MHZ memory modules as this will
give you the fastest overall PC for your money.


Request for Answer Clarification by leonchik-ga on 25 Aug 2006 12:37 PDT
Yes, but my question is about FSB, and not memory itself...or i must
haven't understand the difference between FSB and memory speed?...
FSB is clock of CPU or memory? in the motherboard manual there are
only 3 options for FSB - 500, 800, 1066...

Request for Answer Clarification by leonchik-ga on 25 Aug 2006 12:40 PDT
sorry, only 800 and 1066

from this link:

"Support for an Intel® Core?2 Duo processor in an LGA775 socket with a
1066 or 800 MHz system bus"
i understand from this, that E6600 should work ONLY or at 800 or 1066, right?
so on what it depends?

Request for Answer Clarification by leonchik-ga on 25 Aug 2006 12:43 PDT
my original thoughts was that 667 caus 800Mhz bus, and 800 cause 1066MHz bus...
or i'm wrong, or i just don't understand something :)

Request for Answer Clarification by leonchik-ga on 25 Aug 2006 12:49 PDT
i mean originally i thought that MEMORY 667 cause FSB 800, and MEMORY
800 CAUSE FSB to be 1066....

Clarification of Answer by keystroke-ga on 25 Aug 2006 17:52 PDT
800MHZ memory will cause 800 MHZ FSB, 800MHZ CPU will cause 800MHZ FSB.

Your machine can only run at the slowest common denominator (1066 cpu,
800 memory = 800 FSB. 800 cpu, 1066 memory = 800 mhz bus.)

The FSB is the speed at which data is moved along the motherboard.

This website will help you understand what the Front Side Bus.

Unless you manually set the bus speed faster than what the machine can
handle it will revert back to the slowest common speed for the items
on the motherboard.

As the Intel data sheet specifies that the motherboard CAN use 667 MHZ
FSB applying 667 MHZ memory would cause the FSB to settle at 667 MHZ.
However your CPU cannot take 667 MHZ natively so you would be doing it
a GREAT disservice.

You are best off getting the 800 MHZ memory. The reason I say this is
because the motherboard, memory and CPU all support 800 MHZ natively.

leonchik-ga rated this answer:5 out of 5 stars and gave an additional tip of: $1.00
Thank you! You really helped me.

Subject: Re: FSB and Memory
From: keystroke-ga on 28 Aug 2006 19:37 PDT
Thanks for the five stars and the tip! :)

I'm glad that my information was helpful.
Subject: Re: FSB and Memory
From: guish-ga on 31 Aug 2006 07:04 PDT

The FSB is determined solely by the CPU. In your case E6600 Conroe CPU
on your DG965WH mobo, the FSB will be 1066MHz.

The FSB is a bus between the CPU and the MCH (Memory Conroller Hub -
G965 in your case).

The memory channel is independent from the FSB and is between the MCH
and the memory DIMMs.
Your GMCH (965) supports up to 800MHz DDR2 DIMMs. It also supports
dual-channel configuration. Therefore, when working in dual channel
(if you have 2x1G DIMMs) then they should be inserted one per channel
(One to the blue slot and one to the black slot).

In order to have a balanced memory to FSB system, in your 1066MHz FSB
and dual channel setup, a 533MHz DIMM is sufficient
(2x533MHz=1066MHz). Going to faster clocked DIMMs will not necessarily
improve you performance dramatically.
Lower CAS latency DIMMs will also only improve things, but again, not dramatically.

In conclusion, your CORSAIR 667MHz 2G memory is more then suitable to
your 1066MHz FSB system that is hard determined by your Conroe E6600


Subject: Re: FSB and Memory
From: leonchik-ga on 01 Sep 2006 03:06 PDT
Guish, realy-really thank you!

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