Which dual channel RAM?

[Vormulac]

Hi all,

I am planning to upgrade the ram in my A7n8x-deluxe by going for a 1Gb
matched pair, in order to make use of the dual channel capability of this
board. Does anyone have any recommendations for what ram to use? I've got
about £150 to throw at this.
Speaking of which, does ayone have any experience of Geil ram, particularly
the Golden Dragon pairs?

Thanks all.

 

[Doug Ramage]

Hi all,

I am planning to upgrade the ram in my A7n8x-deluxe by going for a 1Gb
matched pair, in order to make use of the dual channel capability of this
board. Does anyone have any recommendations for what ram to use? I've got
about £150 to throw at this.
Speaking of which, does ayone have any experience of Geil ram, particularly
the Golden Dragon pairs?

Thanks all.

I have had this mobo for nearly a year, and you don't need a "matched" pair
to run dual channel.

I have 2 x256Mb PC3200 plus 1 x 512Mb PC3200 - both TwinMOS. You just need
to remember to put them in the correct slots.

 

[Andrew]

I am planning to upgrade the ram in my A7n8x-deluxe by going for a 1Gb
matched pair, in order to make use of the dual channel capability of this
board. Does anyone have any recommendations for what ram to use? I've got
about £150 to throw at this.

Crucial always works well for me, and is well priced.

 

[Vormulac]

Hi Doug,

Thanks for your reply. So do you have all three slots filled and it's still
making use of the dual channel? Interesting!

 

[Ben Pope]

Hi Doug,

Thanks for your reply. So do you have all three slots filled and it's
still making use of the dual channel? Interesting!

Well... there's RAM in both channels... why not?

Ben

 

[Hinnerk van der Felde]

I am planning to upgrade the ram in my A7n8x-deluxe by going for a 1Gb
matched pair, in order to make use of the dual channel capability of this
board. Does anyone have any recommendations for what ram to use? I've got
about £150 to throw at this.

Had 2x 512 MB Infineon ram running in dual channel mode, but the system
crashed every two minutes. Changed it to Samsung, which are on the list of
Asus' "qualified vendors" and the system runs stable like hell (eMule,
gaming whatever for days).

Never would use memory which is not on the qualified vendors list again.

Hinnerk

 

[Gordon Scott]

Hi all,

I am planning to upgrade the ram in my A7n8x-deluxe by going for a 1Gb
matched pair, in order to make use of the dual channel capability of this
board. Does anyone have any recommendations for what ram to use? I've got
about £150 to throw at this.
Speaking of which, does ayone have any experience of Geil ram, particularly
the Golden Dragon pairs?

Thanks all.

I'm getting great mild OC performance out of my 3200 hynix memory 6 3 3 2

Gordon

 

[Doug Ramage]

Hi Doug,

Thanks for your reply. So do you have all three slots filled and it's still
making use of the dual channel? Interesting!

Yes, but one must distinguish between "slots" and "channels" - they are not
interchangeable.

Slots (sockets) 1 & 2 = Channel 1
Slot (socket) 3 = Channel 2

So for 2 sticks of RAM, you can use slot 1 or 2 for a stick, and slot 3 for
the other stick. But NOT slots 1 and 2.

For 3 sticks of RAM ( e.g. 2 x 256Mb and 1 x 512Mb), the 2 x 256Mb should be
in slots 1 & 2, and the 512Mb stick in slot 3.

See page 14 of the manual for details.

 

[Deathwish]

In the manual for my P4C800-E Deluxe it states: "DIMM's installed in any
three sockets will function in single-channel mode." It's true that you
don't necessarily need a matched pair to run in dual-channel mode, because
the characteristics of the sticks may be close enough to function in
dual-channel, but they MUST be installed in pairs. One pair and a single
stick by itself doesn't qualify for that...

 

[Ben Pope]

In the manual for my P4C800-E Deluxe it states: "DIMM's installed in any
three sockets will function in single-channel mode." It's true that you
don't necessarily need a matched pair to run in dual-channel mode, because
the characteristics of the sticks may be close enough to function in
dual-channel, but they MUST be installed in pairs. One pair and a single
stick by itself doesn't qualify for that...

I missed the beginning of this thread.

From what I understand, you are correct.

With the nForce chipset, you can use 3 DIMMs and get Dual Channel.

Ben

 

[Vormulac]

Hi Doug,

Thanks for clearing that up for me, and thanks to everyone for their input.

All the best.

 

[Guardian]

In the manual for my P4C800-E Deluxe it states: "DIMM's installed in any
three sockets will function in single-channel mode." It's true that you
don't necessarily need a matched pair to run in dual-channel mode, because
the characteristics of the sticks may be close enough to function in
dual-channel, but they MUST be installed in pairs. One pair and a single
stick by itself doesn't qualify for that...

A related question..... Would there be a better performance gain running in
single channel mode with 3 sticks of ram (1 gig total) or a matched pair
running in dual channel mode (512mb total). Winxp Pro is the operating
system.

 

[Ed]

Yes, but one must distinguish between "slots" and "channels" - they are not
interchangeable.

Slots (sockets) 1 & 2 = Channel 1
Slot (socket) 3 = Channel 2

So for 2 sticks of RAM, you can use slot 1 or 2 for a stick, and slot 3 for
the other stick. But NOT slots 1 and 2.

For 3 sticks of RAM ( e.g. 2 x 256Mb and 1 x 512Mb), the 2 x 256Mb should be
in slots 1 & 2, and the 512Mb stick in slot 3.

See page 14 of the manual for details.

Would 3x256 make it slower then? Hmmmm I've tested 2x256 and 3x256 in
dual CH modes, as far as benchmarks go there was no difference at all.

Ed

 

[Doug Ramage]

A related question..... Would there be a better performance gain running in
single channel mode with 3 sticks of ram (1 gig total) or a matched pair
running in dual channel mode (512mb total). Winxp Pro is the operating
system.

I would be most surprised if there was a significant difference - as both
would be in dual channel mode. Also, dual channel mode does not make much
difference anyway - probably a max of 5%?

 

[Paul]

In the manual for my P4C800-E Deluxe it states: "DIMM's installed in any
three sockets will function in single-channel mode." It's true that you
don't necessarily need a matched pair to run in dual-channel mode, because
the characteristics of the sticks may be close enough to function in
dual-channel, but they MUST be installed in pairs. One pair and a single
stick by itself doesn't qualify for that...

There are subtle differences between Intel and AMD chipsets and
processors.

1) The Pentium processor has a 64bit data bus and transfers data four
times per bus clock cycle. This is a better match for two DIMMs
that transfer data twice per memory clock cycle. In memtest86, I
see a 30% difference between single and dual channel modes.
2) The Athlon processor has a 64bit data bus and transfers data twice
per bus clock cycle. The Athlon is a match for the bandwidth coming
from 1 DDR Dimm. As people can attest to here, running dual channel
gives you a 5% improvement.

3) The 875/865 Northbridge chips DRAM controller operates a matched
pair of DIMMs positioned in the correct sockets only, as an
"Uber DIMM". The two DIMMs appear to be 128 bits wide and they
receive the exact same command at the exact same time. When
DIMMs are not placed in this particular configuration, the
controller reverts to running DIMMs individually, at 64 bits
transfer from each (so-called virtual single channel). Three
DIMMs cannot operate in dual channel mode.
4) The Nforce2 Northbridge memory controller has three separate
address/control busses. Matching to get dual channel operation
is relaxed, compared to the Intel implementation. The controller
alternates between the two channels, so as long as the amount of
memory on each channel is equal (i.e. 2x256 on one channel, 1x512
on the other), the chipset can do dual channel.

It isn't safe to compare the two product lines directly, as they are
worlds apart. So, one person's comments about their Pentium experience
may not be appropriate for another person's Athlon problem, and vice
versa.

HTH,
Paul

 

[Ed]

4) The Nforce2 Northbridge memory controller has three separate
address/control busses. Matching to get dual channel operation
is relaxed, compared to the Intel implementation. The controller
alternates between the two channels, so as long as the amount of
memory on each channel is equal (i.e. 2x256 on one channel, 1x512
on the other), the chipset can do dual channel.

Hmmmm I don't get it, I run 3x256 on my Nforce2 ultra and the BIOS
(A7N8X) says Dual CH. on boot up, CPU-Z also says ram is in Dual, and
running dual ch with 2x256 or 3x256 benchmark scores are basically
identical, I don't see any performance hit with 3x256, sounds like I
should.

Ed

 

[Ben Pope]

Hmmmm I don't get it, I run 3x256 on my Nforce2 ultra and the BIOS
(A7N8X) says Dual CH. on boot up, CPU-Z also says ram is in Dual, and
running dual ch with 2x256 or 3x256 benchmark scores are basically
identical, I don't see any performance hit with 3x256, sounds like I
should.

You don't need the same amount of RAM on each channel.

Ben

 

[Paul]

You don't need the same amount of RAM on each channel.

Ben

Can you see a performance difference between running in the Dual
Channel area and the rest of the memory ? Let us take the case
of 3 x 256MB. It would look like this:

Ch.1 Ch.2
256MB <--- Controller cannot alternate
256MB + 256MB <--- Controller can alternate
from channel to channel

Perhaps you'd need a home brew program, that allocates a block
of memory, then does a bandwidth test. You'd have to launch
a whole bunch of these, to fill past the "dividing line".

Paul

 

[RockitFX]

I have a question realtive to the "paring" of ram for channels and
sockets...in my case I have 2 512 chips... i originally had them both
in channel A, but is it OK to have a chip in each channels slot 1 to
take advatage of the dual channel capabilities...keep in mind the slot
2 on both channels are empty and the bios is telling me im in dual
channel mode. Basically i want to make sure im not causing any harm or
slowing my machine becasue the second slots are empty (untill i buy
more ram down the road).

Channel A
slot1 - 512
slot2 - 0

Channel B
slot1 - 512
slot2 - 0

mobo -intel d865perl

 

[Philip Callan]

Basically i want to make sure im not causing any harm or
slowing my machine becasue the second slots are empty (untill i buy
more ram down the road).

Egads man, your speeding your RAM bandwidth up a good chunk, not slowing
down, and no, it wont harm anything

My only advice, get more 512's, 1GB sticks arent that shit hot, unless
you know your getting quality guaranteed ram, not generic.

if you get 2x1GB, move the 512's to slot2, and move the 1GB's into slot1.

Channel A
slot1 - 512
slot2 - 0

Channel B
slot1 - 512
slot2 - 0

mobo -intel d865perl

nice little board...