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Dual Channel RAM

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Hello all.

On this page: http://h10025.www1.hp.com/ewfrf/wc/document?docname=bph03886&lc=en&cc=us&dlc=en&product=3546122 HP states that in order for dual channel memory to work all the RAM fitted must be absolutely identical - right down to the fact that boards must be either all single-sided or double-sided.

First I suppose that this is true? I have in my HP, four 1GB boards; three are double-sided and one is single sided; all are PC5300 667MHz.

Would appreciate your comments and would like to know if there is a utility whereby I can check the status - i.e. if the computer is running in dual or single channel mode.

Thanks in advance.

Paul

31 replies

by older mycroft

In that case your best bet would be to run with 2 x 1 GB + 2 x 512 MB, filling all four memory slots with pairs matching in configuration and size.

3GB is your maximum usable RAM for XP. :)

by var1016

Hello there.

I am not sure that "revert" is the right word, I prefer "upgrade"!

Thanks to all the help both from the stalwarts here and from HP I did: I installed XP Home successfully, now I have replaced that with XP Pro and after some difficulties, (six installs!) this is working fine. The computer came with 2 x 1GB running in dual channel mode. I first added 2 x 512MB, but these are single-sided DIMMs whilst the originals are double sided. I ordered two 1GB cards for a "project", but these are different, one single and one double. Anyway I plugged them in and now Process Explorer tells me I have 3.6GB available.

I would like to know how to find out whether the computer is running dual or single channel - I am really just curious about this. For what I run the computer all this is really quite unnecessary, but that's what enthusiasm does!

Best wishes

Paul

by nepenthe0

Download and install the free SIW utility:

http://www.gtopala.com/

Check the specs SIW generates for the motherboard and memory. Also, you might like to review this excellent (72 pages) monograph on memory:

http://tinyurl.com/3ew39f

It's a zipped folder. Unzip the folder, open the subfolder, and save the .pdf monograph to disc.

Rick/Portland, OR

by var1016

Thank you.

I have a lousy Internet connection today so SIW is still downloading; I have downloaded the memory article and shall read it up.

Thanks for your support.

Paul

by nepenthe0

Your English improves with each post...

I'm amazed you manage so well - the winter I studied in Paris (1969), I struggled to communicate in French, and the natives refused to speak English as matter of principle. Will you be posted there long?

Rick/Portland, OR

by var1016

Hello and thanks. I just ran CPUID; my memory is running in single channel mode. I am annoyed to read that the memory speed for each of the four sockets is 333MHz. Now I have purchased two 667MHz cards, do I assume that the original memory is therefore only 333MHz and that therefore I must buy even more RAM?

Thanks again - that's a super utility.

Paul

by older mycroft

My RAM is dual channel 667MHz but it also shows up @ 333MHz in the CPUID result page.

If you haven't already got it, get hold of S.I.W. from here:

http://www.gtopala.com/siw-download.html

It will confirm (and reassure you) that your RAM is 667MHz.

OH Smeg will be along in a minute I'm sure to ratify the matter for both of us!! :D

by var1016

Don't panic Mr Mainwaring!

Well SIW does confirm that all the cards are 667MHZ and are running at 333MHz. It also confirms that I have about 3.6GB available. I have ordered another double sided card so when that arrives we shall see!

Mind you, if my rubbishy Internet connection gets any slower (are you listening FREE.fr??)I might as well chuck the lot in the dustbin and buy a typewriter!

All the best

Paul

by var1016

Ha ha! Well Free is a major provider in fact rather than some back street outfit; but they are pretty crap really. In fact here in the sticks, we have had ADSL only for about 18 months, so perhaps things will improve. Mind you I am paying for 1GB/s and getting about 25% of that most of the time. I have ordered a Linksys modem/router so I can connect up the other computer which I am going to tart up. Perhaps the Linksys modem is better than what Free calls "Freebox"?!

Paul

by var1016

But I am English! My French is terrible even though I have been here three years; I have no desire to return to England and expect to stay here until the end!

OK I downloaded SIW and am staggered to see the amount of information it provides. Depressing though to think that I shall never understand a fraction of it. Anyway it didn't tell me whether I was running in dual or single mode, but I have the answer now. It does say that Core #1 of the CPU is at 2?C which I find rather hard to believe (Core #0 is at 17?C it says). Here in Haute Savoie (at about 3000ft)it does get bloody cold, but not generally in June!

Anyway, thanks again and forgive me, I am rather keen to learn a bit more about this 'ere computin' business.

Best wishes,

Paul

by rob miners

with two sticks of identical RAM. Here are some picks.

http://www.devhardware.com/c/a/Memory/Dual-Channel/1/

The quickest way to check is to turn off the splash screen in BIOS and restart the PC so you can see what is loading. If you are quick enough you will be able to hit the Pause Button and the information will be displayed top left on the screen it is normally shown under Memory Testing.

With two sticks of RAM, if the board has four memory slots you insert one stick near the CPU, miss a slot and place the other in there. That is using Dual Channel. If you have four identical sticks of RAM and put them in all of the slots that is also using Dual Channel.

If you put two sticks of RAM in the first two slots you will be running on Single Channel.

by var1016

Thanks. Yes, that's right: the original setup was two Samsung PC5300 667MHz cards in slots 3 & 4 which I believe was dual channel configuration. These cards are double sided, so as I said I have ordered one more double-sided card (Corsair) to go with the other Corsair card and to replace the Kingston single-sided card I have. All are PC5300 667MHz. I hope they don't all have to be the same make as well!

Thanks

Paul

by rob miners

What you are getting should do the trick. ;)

Have you had a play with the Pause button yet. :)

by nepenthe0

I just checked your whereabouts with Google Earth, and I see you located right at the Swiss border, and practically a stone's throw from northern Italy. Now I see why foggy London has lost its allure. 5000 feet - must be nice in the summer.

Yeah, knew you were English from our prior exchange, just wanted to pull your leg...

I must confess that I don't understand a fraction of the information retrieved by SIW. It gave me enough information about the motherboard so that I could archive the correct SATA drivers should I ever need them.

As always, good to hear from you.

Rick/Portland, OR

by var1016

That's right, I am about 30km (20 miles) south of Geneva and about 200km (125 miles) from Turin. It is a beautiful location now that finally we have some sunshine!

SATA drivers: another subject I need to learn about!

All the best and nice to hear from you. I look forward to more help in due course!!

Paul

by var1016

It's jolly complicated isn't it??!

I have noticed during all the reinstallations I have made recently that when I load the NVIDIA chipset drivers, I get a popup which tells me that Windows has detected (hard disk drive number). Until now I had assumed that ths meant that the HDD was now running in SATA mode. I had better have another look at SIW I think and try to understand better...

Best wishes

Paul

by nepenthe0

SATA is the acronym for Serial Advanced Technology Attachment. It refers to the standard that specifies the cabling to your hard drive.

The older hard drives were of IDE genre (Integrated Drive Electronics). The IDE drive had a long 40-pin connector. The new SATA drives have a much narrower profile connector.

The issue may arise should you ever reinstall the operating system using a [i]clean install[/i] method. This is the preferred method, because it wipes the code from the hard drive, so that corrupted drivers and .dll fragments are effectively assassinated.

The glitch comes when the Windows CD doesn't have SATA drivers, and the installation fails because the hard drive is not [i]detected[/i].

So be forewarned. I recommend downloading and archiving your SATA drivers for safekeeping should you ever need them. Follow the instructions from the nLite link I just sent you.

Use SIW to determine the motherboard information for the appropriate drivers (yours will almost certainly be 32-bit drivers).

It's less complicated once you actually dive into it. If your computer shipped with bundled software and you have a repair/installation CD for that machine, the SATA drivers should already be on that CD.

The problem comes with Windows SP1 CDs that lacked SATA drivers, and apparently some SP2 CDs also shipped without SATA drivers.

Rick/Portland, OR

by older mycroft

I'd never heard of it before, then why would I ?

Courtesy of the Google translator (I've recently forgotten more French than I ever learned !!) it appears to mimic one or two of the less believable ISPs masquerading as service companies here in the UK, in terms of bold promises with little to back it up.

Don't you have any alternatives at your disposal? - as France's bandwidth is at least on a par with the better serviced in the UK (that does NOT include the Highlands of Scotland ;) ).

by oh smeg

You need Identical RAM in Pairs fitted in Banks.

Normally if you have room for 4 sticks of RAM that allows you 2 Banks of 2 sticks which can be different provided that the RAM within the individual Bank is the same.

However here as you have 1 Matched Pair and 1 unmatched pair you will need to change 1 stick if you wish to run the computer with Dual Chanel RAM. When you fit different RAM to a M'Board in a Pair this normally returns the RAM to Single Chanel Configuration even if you already have a Dual Chanel Configuration correctly setup.

If you look at the M'Board you should see the 4 RAM Sockets and see 2 lots of 2 colors. When you want to run Dual Chanel RAM you need to fit the Matched Pair to the Same Color Sockets which is generally Sockets 1 & 3 or 2 & 4 but you need to look at the individual M'Board. If you have 3 RAM Sockets and want to use Dual Chanel RAM you can only use 2 RAM Sticks fitted tot he Matching Sockets when you fit the third Stick it returns the RAM to Single Chane. But again this all depends on the M'Board Maker and how they make use of the Chip Set that they use on that M'Board.

Enjoy you seem to be a glutton for punishment Paul. ;)

Col

by ozi eagle

Hi,

What Hal says is vis a vis the colour of the RAM socket is the logical way, however, my mobo is the exact opposite. For dual channel you must have a stick in each of two different colours.

My advice double check your mobo manual.

Herb

by var1016

Thanks for this, I think I have it right, but it's always worth another look!

Paul

by var1016

For your support.

The problem is that I am, with my fading brain and memory (not RAM!) trying to learn in ten minutes what you experts have learned at university and in your jobs!

The EC2 motherboard has four sockets; originally just sockets 3 & 4 were used to run 2GB in, I believe, dual channel mode. These are coloured blue. I am now using the two white sockets for my extra RAM.

All the best

Paul

by dmiles

Dual Channel-enabled memory controllers utilize two 64-bit data channels, resulting in a total bandwidth of 128 bits, to move data from RAM to the CPU.

In order to achieve this, the DDR SDRAM memory modules must be installed into matching memory slots, which are usually color coded on the motherboard. Each memory module in each slot should be identical to the one in its matching slot. It's also possible to use similar memory sticks from different manufacturers or different production series as long they are of the same size, specification, the same number of memory chips and internal organization.

Dual channel technology was created to address the issue of bottlenecks. Increased processor speed and performance requires other, less prominent components to keep pace.

The most conspicuous of these parts is the memory controller, which regulates data flow between CPU and the system memory (RAM). The memory controller determines the types and speeds of RAM as well as the maximum size of each individual memory module and the overall memory capacity of the system. There are many memory controller designs; prior to 2003, the most common was the single channel configuration. Among its advantages are its low cost and flexibility. Its ability to produce a bottleneck effect arises when it is unable to keep up with the processor, leaving it with nothing to process while the memory controller is struggling to keep up with the data flow. Under the single channel architecture, any CPU with a bus speed that is greater than the memory speed would be liable to fall prey to this bottle-neck effect.

The dual channel configuration alleviates the problem by doubling the amount of available memory bandwidth. Instead of a single memory channel, a second parallel channel is added. With two channels working simultaneously, the bottleneck is reduced. Rather than wait for memory technology to improve, dual channel architecture simply takes the existing RAM technology and improves the method in which it is handled. While the actual implementation differs between Intel and AMD motherboards, the basic theory stands.

by var1016

Thank you very much for taking the time to write that excellent summary of Dual Channel Operation, I am most grateful.

I have bookmarked your message for re-reading - as I told OH Smeg, my brain is not what it was (and it wasn't all that then!).

Best wishes

Paul

by var1016

Thanks: in fact over the past week or so I have actually made about six or seven clean installs of XP Home or XP Pro (OH Smeg knows all about it!). I have had no trouble at all with the installation process so I presume that my 2006 version of XP Pro that I am using has the necessary files. I have added SP3 and have had no trouble with that either. In the Tiny article reference is made to Intel drivers; I trust that these will work with my AMD set up?

Thanks again
Paul

by nepenthe0

OH Smeg would be the one to advise you regarding this. From what you have posted, it is unlikely to ever become an issue. You obviously already have the SATA drivers on your recovery CD.

It's always good to consider these issues, because installations can fail for a number of reasons, and it helps to have a good understanding of the process in order to troubleshoot glitches.

Rick/Portland, OR

by var1016

Thanks.

I did search on Raid and Sata and found many files in Nvidia directories, which is encouraging...

And as you say, at least the OS installed!
Best,

Paul

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