Dual Channel RAM on XP Pro


M

Mark G.

So XP Pro can only handle 3.4 gigs of RAM, correct? I have (4) dimm slots
with (2) 1 gig sticks achieving a total of 2 gigs in dual channel mode. This
leaves 2 open. I was only wanting to add another gig. Therefore I thought I
would just get a 1 gig stick. If I stick one stick in 1 of the 2 remaining
slots, will it mess up the dual channel mode on the other 2 sticks? If it
does, will I still be much better off with this extra gig over using dual
channel on 2 of the sticks? I had thought about getting (2) 512mb sticks to
fill the other 2, but it seems economically, I would be better off
purchasing 1 stick. Could I get some input and opinions on this please?
Thanks much!
 
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P

Pegasus \(MVP\)

Mark G. said:
So XP Pro can only handle 3.4 gigs of RAM, correct? I have (4) dimm slots
with (2) 1 gig sticks achieving a total of 2 gigs in dual channel mode.
This leaves 2 open. I was only wanting to add another gig. Therefore I
thought I would just get a 1 gig stick. If I stick one stick in 1 of the 2
remaining slots, will it mess up the dual channel mode on the other 2
sticks? If it does, will I still be much better off with this extra gig
over using dual channel on 2 of the sticks? I had thought about getting
(2) 512mb sticks to fill the other 2, but it seems economically, I would
be better off purchasing 1 stick. Could I get some input and opinions on
this please? Thanks much!

Nothing to do with Windows - I would try a hardware newsgroup.
 
P

Paul

Mark said:
So XP Pro can only handle 3.4 gigs of RAM, correct? I have (4) dimm slots
with (2) 1 gig sticks achieving a total of 2 gigs in dual channel mode. This
leaves 2 open. I was only wanting to add another gig. Therefore I thought I
would just get a 1 gig stick. If I stick one stick in 1 of the 2 remaining
slots, will it mess up the dual channel mode on the other 2 sticks? If it
does, will I still be much better off with this extra gig over using dual
channel on 2 of the sticks? I had thought about getting (2) 512mb sticks to
fill the other 2, but it seems economically, I would be better off
purchasing 1 stick. Could I get some input and opinions on this please?
Thanks much!

To make a 3GB configuration, you can do

2x1GB + 2x512MB

That maintains the dual channel feature.

If, on the other hand, you tried 3x1GB on a four
slot board, what happens, depends on the chipset.

1) Some chipsets are truly dual channel, and won't
run a 3x1GB configuration. If you're lucky, the BIOS
will ignore the odd stick, and you'd get 2GB
usable as a result. Poorly written BIOS might only beep.

2) Some chipsets drop down to virtual single channel
mode, when 3x1GB are used. That means the memory
bandwidth drops a bit, but 3GB is detected by
Windows. On a given memory access, only one stick
is accessed at a time.

3) The third response, is called Flex Memory. The
dual channel portion runs at full speed (2x1GB).
The odd stick runs in single channel configuration.
Flex Memory is a feature of relatively recent
Intel chipsets. The first instance of this behavior
that I've seen, was on Nforce2 from Nvidia. So they
deserve credit for introducing it.

Buying 2x512MB is likely to do the job for you.

Buying 2x1GB extra will also work, and the hardware/software
will simply ignore the unusable portion. In the case
of memory types like DDR2 or DDR3, where mostly big
sticks are available, this is also a pragmatic solution.

When you ask a question like this, it really helps to mention
either the brand + model number of the computer, or the
brand + model number of the motherboard. Alternately,
even mentioning the chipset on the motherboard helps.
You can get some info about your computer, with CPUZ.

http://www.cpuid.com/cpuz.php

When the new memory arrives, there are two tools you can
use. Memtest86+ from memtest.org, is a memory tester, and
you can either get a floppy or a CDROM based version. It
tests all but less than 1MB of the total memory. It even moves
the executable out of the way, and tests underneath. If you can
do a couple passes error free with that, only then should you
boot into Windows. Once in Windows, you can use Prime95 from
mersenne.org and its "torture test" to complete your memory
testing. That is the test procedure I just finished using
on this computer, with its new memory. Prime95 will stop on
the first error detected, and at least a four hour run is
recommended.

Paul
 
M

Mick Murphy

Ever thought about answering an OP's question, mmm?
He is running XP Pro; so it IS a Windowsxp.general question.
 
M

Mark G.

Wow Paul... thanks for the very informational post!

You are right... I should have posted more hardware info on my computer. My
bad. My computer is an AMD Athlon 64 X2 5600+ processor and then a MSI
motherboard. The motherboard is model "MS-7250 and uses the Nvidia nForce
570 SLI chipset with the MS-7250 version 1.7 BIOS. With that info, would you
say that a better option is the 512mb x 2 option rather than the 1 gig
option?

My current RAM is Mushkin DDR2 800 PC 6400 with heat spreaders and a latency
of 5. Was thinking of getting a different brand of ram, but still good ram
and keeping the same speed and such. Am thinking this would be fine and if
anything about the pieces of ram differs in for instance the latency, then
the computer will just clock down to that.

And lastly, after checking Newegg's site, it would be about the same price
for either (1) 1 gig stick or (2) 512mb sticks. Maybe that in itself answers
my question?

Got more to add? Anyone else wanna pipe in? Thanks thus far!
 
J

John John (MVP)

At the price of RAM nowadays it isn't worth bothering with the question
at hand. Paul gave us a *very good* explanations of how things work and
of what may or may not happen when you add RAM. In dual channel RAM the
recommendation is always to add RAM in matched pairs and I suggest that
you follow that recommendation. The price difference between 512MB and
1GB sticks is almost not worth mentioning, get two 1GB sticks and stuff
the machine to a full 4GB and let the chips fall where they may...
Depending on the hardware that is installed in the box you will end up
with Windows being able to use anything between about 2.5 and 3.5GB of
RAM, most users end up being able to use about 3.2GB.

John
 
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P

Paul

Mark said:
Wow Paul... thanks for the very informational post!

You are right... I should have posted more hardware info on my computer. My
bad. My computer is an AMD Athlon 64 X2 5600+ processor and then a MSI
motherboard. The motherboard is model "MS-7250 and uses the Nvidia nForce
570 SLI chipset with the MS-7250 version 1.7 BIOS. With that info, would you
say that a better option is the 512mb x 2 option rather than the 1 gig
option?

My current RAM is Mushkin DDR2 800 PC 6400 with heat spreaders and a latency
of 5. Was thinking of getting a different brand of ram, but still good ram
and keeping the same speed and such. Am thinking this would be fine and if
anything about the pieces of ram differs in for instance the latency, then
the computer will just clock down to that.

And lastly, after checking Newegg's site, it would be about the same price
for either (1) 1 gig stick or (2) 512mb sticks. Maybe that in itself answers
my question?

Got more to add? Anyone else wanna pipe in? Thanks thus far!

The right solution is 2x1GB + 2x512MB. If I look in the K9N Ultra
manual, they show a pair in 1-3, a pair in 2-4, or a total of four
sticks as dual channel configurations. So there isn't a good
reason to be using 3x1GB. (That is the cheapest solution, but
not the only solution.)

This article tests sensitivity to memory speed, so you can get some
idea which applications benefit.

http://www.digital-daily.com/cpu/athlon_64_x2_am2/index03.htm

Paul
 
P

Pegasus \(MVP\)

If you have a look at this newsgroup then you'll spot lots of my technical
responses, not just referrals.

You claim that this is a Windows general question. Why is it not an Apple
Mac question? Or a Linux question? Is the operating system of any relevance
in the OP's question?
 
M

Mike Hall - MVP

Mark G. said:
Wow Paul... thanks for the very informational post!

You are right... I should have posted more hardware info on my computer.
My bad. My computer is an AMD Athlon 64 X2 5600+ processor and then a MSI
motherboard. The motherboard is model "MS-7250 and uses the Nvidia nForce
570 SLI chipset with the MS-7250 version 1.7 BIOS. With that info, would
you say that a better option is the 512mb x 2 option rather than the 1 gig
option?

My current RAM is Mushkin DDR2 800 PC 6400 with heat spreaders and a
latency of 5. Was thinking of getting a different brand of ram, but still
good ram and keeping the same speed and such. Am thinking this would be
fine and if anything about the pieces of ram differs in for instance the
latency, then the computer will just clock down to that.

And lastly, after checking Newegg's site, it would be about the same price
for either (1) 1 gig stick or (2) 512mb sticks. Maybe that in itself
answers my question?

Got more to add? Anyone else wanna pipe in? Thanks thus far!


You could use 4 x 1Gb sticks and possibly have 3.5GB at your disposal


--
Mike Hall - MVP
How to construct a good post..
http://dts-l.com/goodpost.htm
How to use the Microsoft Product Support Newsgroups..
http://support.microsoft.com/default.aspx?pr=newswhelp&style=toc
Mike's Window - My Blog..
http://msmvps.com/blogs/mikehall/default.aspx
 
P

Pegasus \(MVP\)

Mick Murphy said:
Ever thought about answering an OP's question, mmm?
He is running XP Pro; so it IS a Windowsxp.general question.

I should add that it makes no difference to me where the OP posts his
question - why should it? However, if the OP wants to get the best hardware
advice then he should post where the hardware experts hang out. If you ask a
dentist to fix a broken bone then he'll probably refer you to a medical
doctor, for obvious reasons.
 
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M

Mick Murphy

The Newsgroup is General!
--
Mad Mike


Pegasus (MVP) said:
I should add that it makes no difference to me where the OP posts his
question - why should it? However, if the OP wants to get the best hardware
advice then he should post where the hardware experts hang out. If you ask a
dentist to fix a broken bone then he'll probably refer you to a medical
doctor, for obvious reasons.
 
M

Monitor

Dear Mad Mike,

I feel a little sorry for you: You have obviously become a victim of Bill
Gates' brainwashing efforts. He has succeeded in getting the idea into your
head that Computers = Windows. Nothing could be further from the truth. The
RAM question is "generally" related to computers but it has nothing to do
with Windows, not in general and not in particular. Have you noticed that
the word "Windows" does not even occur in the original post? Perhaps a quick
summary would be helpful:
- Hardware: All the things you can touch in a computer, e.g. hard disk,
memory, CPU chip.
- Software: All the things that are programmed into a computer, e.g. the
operating system (Windows would be one of many examples) or the various
applications (Firefox or Excel are examples).

It's probably a good idea to keep these facts in mind when telling other
respondents what to write.
 
L

Lil' Dave

Along the line of medical professionals, a general practicioner may send a
patient to a specialist. That is appropriate advice along those lines of
thinking. If a specialist regarding hardware (RAM) and bios setup replies
in the general newsgroup, fine. The surgeon came to the M.D.'s aid. That
does not make the recommendation by the general practicioner any less
appropriate.
 
B

Bob I

I suppose we will be fielding questions about Colin Powell as on topic
too? I hear he has used Windows XP.
 
J

Jason

An MVP in this channel may know windows fauling hardware but not know much
about motherboards in genearl - the orignal poster should ask motherboard
manufacturer or person he/she bought computer off.
 
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L

Lil' Dave

LIke any other question posed at any newsgroup, many people find it easier
for others to find their answer. Most MVPs don't fight this, and go with
the flow. Point to a more likely newsgroup to get a good answer. MVPs, in
general but not all, are not all that familiar with hardware failures, and
more apt to point to suggestions regarding operating system fixes that don't
address such problems. That is, due to their unfamiliarity, they are not
apt to suspect hardware in cases, at least to me, may be of hardware nature.
And in some cases, firmware or the bios as well. Hardware failures are not
operating system dependent, so there's no such thing as "windows failing
hardware".

Yes, I agree the OP should have gone to the motherboard website or call it's
tech support for the dual channel RAM answer regarding RAM addtions. The
specific answer is based on the specific motherboard and its bios setup. A
former owner regarding this specific question is a doubtful deer in the
headlights look I suspect.
 
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K

Ken Blake

LIke any other question posed at any newsgroup, many people find it easier
for others to find their answer. Most MVPs don't fight this, and go with
the flow. Point to a more likely newsgroup to get a good answer. MVPs,
in general but not all, are not all that familiar with hardware failures,
and


That depends entirely on who the MVP is and what his area(s) of knowleadge
is(are). Most of the MVPs you find here are Windows MVPs, so many of us are
therefore not particularly good at hardware. However some Windows MVPs work
with hardware daily and are very good at it.

Speaking for myself, I am far from being a hardware expert.
 

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