Dual Channel Memory help...

How about the scenario, 4 sticks of 256MB each 200Mhz so total is 800Mhz and 2 sticks of 512 400Mhz, which one will run faster? My understanding the dual channel optimized for double bandwidth compare with the single channel. Single channel share the same pipeline for read and write data where as the dual is read and write data access different pipeline.

Hi

I have a similar issue. Had a 512 Mb DDR400 dual-sided DIMM, and later purchased stock 512 Mb DDR400 (which turned out to be single sided).

Intel 915 chipset recognised the dual channel memory configuration of the 2 sets, but reports a clock speed of 333Mhz, rather than 400Mhz.

Checking each memory stick individually, they both CAN run individually at 400Mhz - has anyone else experienced this?

_____

Didn't you read what I had written above about fan-out and clock speeds? You're one of those with newer mobos which actually down clock as REQUIRED and NEEDED automatically.

Your mobo can't drive 4 sticks at 400, but do just fine at 333. Most mobos can't, some Nvidia's will do 400 if they're all single-sided sticks.

4 single-sided sticks have the equivalent fan-out loading as 2 double-sided sticks.

Thanks for your assistance. I'm new to this, so appreciate your help.

For my clarification, if my 2nd DIMM was DS rather than SS, would the clock speed have remained as 400Mhz? (Likewise, if I changed for 2 xSS)? The intel documentation on their support site for dual channel makes a big play around not mixing SD and SS, but as above it can work.

Also for memory transfer rate, how would 1x512Mb @ 400MHz (Single Channel) compare to 2x512Mb @ 333MHz (Dual channel)?

There is a lot of confusion over numerous internet forums regarding this, so any help gratefully received.

Basically dual channel is you have two pipelines to the processor from the ram instead of one thus you will have more bandwith..


Read here for some information

http://www.sis.com/support/learn/techarticle/dualchannel.htm


http://www.kingston.com/newtech/MKF_520DDRWhitepaper.pdf

hope this helps you understand.

If they were both of the same type - yes, certainly so but the DS would still be inferior in max speed possible relative to the SS.

The question above do not have simplified answers, I'm not going to give you a lengthy, complicated technical answer.

The confusion is simply that most people don't work with super-computers, they had not ever used what was very common hardware but not in typical consumer until now.

Thanks tbrunt3. The 2nd link displays some of the confusion out there I have come across - which contradicts some of the forum comments I have found; extract

In this context, “matching” modules means:
1. Both modules are the same capacity (e.g. both are 256MB, or 512MB)
2. Both modules are the same speed (e.g. both are PC2700 or PC3200)
3. Both have the same number of chips and module sides (e.g. both have the
same number of chips on the module, and both are either single-sided or
double-sided).

1 and 2 are fine, however the 3rd line is the scenario I'm in - but it does appear to work (mobo automatically downsizes memory clockspeed as per neins response).

I'm assuming 2x512Mb DDR400 in dual channel running at 333MHz is an improvement on 1x512Mb DDR400 in single channel @ 400MHz for memory throughput (my main reason for upgrading). If I had 2x512Mb DDR400 in dual channel on Intel 915 chipset (both DS, or both SS) that the memory clock speed would be 400MHz?

Sorry to labour on this - I'll trying to see if I should put effort into either returning 1xSS DIMM, or accepting its not going to make any difference.

HERE is a not so techie answer i try to make it simple..

Basically dual channel is you have two pipelines to the processor from the ram instead of one thus you will have more bandwith..

The dual will be faster but you will need the same ram in the dual slots on your motherboard.. They both have to be the same makes same settings such as lantency..

To break this down even more lets say for dual channel to work on your mother board you will see some slots that are colored these are the dual channel slot they have to have the same type of ram both 256 or both 512 but they have to be the same maker and identical in setings ..

Hope this helps you and not confuse you more.

Thanks again, tbrunt3...

The Kingston link was very helpful....

If Im running 2 matched 256 sticks in DUAL Channel...Im getting something like 1 gig performance... which should be plenty for me for a couple years.

which, I figure by then even the new 64 bit CPUs and PCIexpress will be outdated, lol, and there'll be something even 'BETTER', and all software will be programmed to self-destruct after 6 months anyway, forcing us to sell our grandchildren to buy the technology just to get the mon9iter to turn on etc...

peace,

I heard 2 different side of stories, it said that if the both memories are the same but different the CAS latency, the the motherboard will not running dual channel, it will go back the single channel, another stories said different way, the motherboard will synchonization timing of the memories to make the equivalent CAS latency so it can support to run dual channel. Another question that I just wonder what is the different between PCI express and PC-X on the motherboard, Does PCI express work on the regular AGP slot? also Does PC-X expansion slot will work with 2 SLI video card? Sorry for the long post, I am trying to keeping up the technology. It also cost me too much money lately. Thank for any answer that might helps.

Different manufacturers implemented differently, some implementations are inferior to others.

PCI express is a "Scalable Link Interface", a completely different architecture which has none in common with old time PCI but for the "PCI" in its name. Pertinent link. PCI express closest relative in consumer hardware is AMD's HyperTransport AKA - LDT - Lightning Data Transport. Another newborn relative is Nvidia's "bridge" in their SLI graphic products, Nvidia's bridge is a "Scalable Link Interface".

PCI-X is extended PCI, it is the superset which all of old PCI functions are subsets. It is backward compatible with old PCI.

Yeah, PCI eXpress will not work in old PCI slots, and they wont work in AGP slots either.

New technology, new motherboard.

need help with ASUS A7V880 and GeiL RAM and XP 2500+

I'm having a problem getting the same settings that I had with my old Abit NF7-S board to work on this ASUS A7V880 board.

On my old board, all I had to do was bump up the FSB to get an Athlon XP 3200+. Of course, I have a 2500+ Barton core.

I've also got a matched pair of GeiL Ultra PC3200 (400MHz) DDR memory, and cannot get it to go into dual channel mode. I've tried putting them on the same controller, but single channel only is enabled (wont boot under dual channel). Also tried putting each stick into the blue slots, and it will only recognize one of the sticks.

Can anyone help me get this thing in dual channel mode AND get this thing bumped up to an AthlonXP 3200+ ??

One bad thing about AMD chipset, you can't have 2 pairs of matched memories. You only put 1 matched pair of memory in slot 1 and 3. Try this if it work, I have GA-8KNXP Ultra 64, it has 6 slots, I put 1 GB Geil in 1 and 4 and it run in dual channel with 20% system increase compare with single channel. Make sure you have matched pair of memory, which are must be the same CAS latency and model number. Of course they must have the #MB. Hope this helps. My recommendation for you to buy the motherboard I have, it's very good board and last very long time. Check it out, this is the best board I have ever own.

http://tw.giga-byte.com/Motherboard/Products/Products_GA-8KNXP Ultra-64.htm

*BUMP*


Joined this board soley to thank you guys for this post.
Looked everywhere for info. Finally put the right combo of words in Google and found this post.

Thanks!
Got a Chaintech AMD64 mobo ( S1689 ) a few months ago and a stick of 512M RAM from Crucial. Bought another stick this week. Arrived today...o boy! Wait...it looks different?! Slapped it in.
*beep beep beep*
WTF?!!? Everyone told me if they were the SAME, that it would be fine. The serial number is the same. Well..until you take a closer look. After the serial # is a .xxxx. Of course they don't show the .xxxx part on the website. These are not the same on the 2 chips. One has 8 pieces per side, one has 4 pieces on only one side and is not as tall.
Either works fine alone.
Hopefully they have some of the 8x8's left.
Or they'll exchange my 8x8 for a 4x0.

But anyway, thanks. Just wanted to let you know your place here helped me out. And probbly lots of others that don't post about it.

BTW, the search I used that found you on page 1 of Google was
"AMD64 DUAL CHANNEL".

Wow! Great info here.. I appreciate it! I have a question. I just purchased Patriot DC 2G(1GX2) 184-Pin DDR SDRAM and my mobo (Intel D865PERL) has 4 DIMM slots. I'm only going to use these two sticks, so do I have to (or should) place 1 in slot 1 and 1 in slot 3 or should they be placed in 1 and 2? Or does it really matter? lol Thanks!

I never knew that a dual channel kit is more expensive than two identical DIMMs?! In my case it was cheaper to buy the kit from the same manufacturer.

I think the $60.00 difference mentioned at the beginning might have been like a dual channel kit from OCZ compared to ... let's say ... Azen RAM, since make and model was not given, I had to assume.

Most dual channel kits I have seen are actually slightly cheaper than 2 X of the same module purchased separately. Packaging and all considered.

Happy Computing,
Sharam.

I am about to put together a new computer and am a little short on cash but want to get the most for my money. Is it possible to just buy 1 stick of branded ram now and then buy another in a month or two and still be able to run them in dual channel?
Corsair 1GB 3200 DDR

assuming of course that they are the same brand, speed, etc...

Am I glad to find this site, and you guys had helped me clear out alot of question I had about adding memory and the confusion on DCM(Dual Channel Mode). Thank you so much!

Appreciate it if anyone could help clarify a few more question on "What if..?".

I currently have 1*Ultra 512MB PC3200 DDR 400MHz CL3 on my mobo.
From the discussions on here, seems pretty clear that unless I bought two stick of memory together, getting a matching module in the future even from the same site can be pretty slim.

So sounds like my best bet is to get a set of dual channel kit to run DCM.

(I am using the Ultra brand specifically just to cover the possible issue of brand incompatability assuming CL are the same).

So if I get a dual channel kit-Ultra Dual Channel 1024 PC3200 DDR 400MHz (2x512MB) CL3, add that to my existing Ultra 512MB CL3 module.
The 1 GB dual channel kit will run DCM, along with the other 512 module on single channel, or all 1.5GB stays on single channel or...?

Because on page 1, Th3M1ghtyD8 mentioned

Can someone clarify this part?

FYI if someone is wondering - "there are mobos which allowed 2 seperate dual-channels memory set which also also allowed "different CAS per controller" but not "different CAS per memory device".

He also mentioned

I am curious if the the whole "dual channel memory kit" is just a marketing scheme by manufacturers/retaliers. What is exactly the difference between two matching memory module and a "dual channel memory kit"?

I mean the price difference are huge between the two. It was suggested that if we buy both 2 sticks of branded memory (e.g. Crucial, Kingston, etc) at the same time, from a reputable supplier/retalier they are likely to be identical. If that is true, we would all be saving a lot of money. I am just curious if anyone do it that way, or how many does it that way and if anyone had end up with non-matching memory module?

Also Dtp2005 mentioned

I am confused about what he meant by that.

Thanks for the help.

Just found all the answer I needed in case someone is about to answer my post/questions.

If anyone wants a clear easy explanation on pretty much most of the questions ask on this forum, go to the kingston site for the explanation

http://www.kingston.com/newtech/MKF_520DDRWhitepaper.pdf

Specifically on pg 8 for the explanation on what is 'matching module'

and the diagram on Pg 9 is really easy to clarify it all.