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Discussion Starter #1
Was with my buddy at lunch today helping him buy a motherboard, proc and memory. The MB takes DDR 400, so I went to the shelf and picked up some PC3200... two 512's. My buddy handed the board, proc and memory to the young'in and asked if everything matched up.

Him -> yes, but there is faster memory.
Me -> Faster? MB takes 400, this is 400
Him -> uhhhhh, well there is better memory
Me -> Better?
Him -> This one is faster because of the bigger data channel
Me -> Bigger data channel? What do you mean by that
Him -> A bigger channel means that it can run faster
Me -> Ok, how do you tell it has a "bigger data channel"? It's not on the box, they have the same amount of chips, all DDR has the same amount of gold connectors and they are the same speed.
Him -> uhhhh, uhhh, uhhh, It has a bigger data channel
Me -> Is this something you read, something you were trained on or something you are just repeating.


He left to the back of the store for about 10 minutes and came back up and said...

Him -> This pack is sold in pairs and is rated to go together. The single packs are not rated together.
Me -> So I need to spend a few more dollars to buy the pack that has two of them in the same package because they came down the assembly line side by side.
Him -> no response.

What a laugh I had over that one. To make it worse, my buddy spent the few more bucks for the dual pack.

I appreciate help just like the rest of you, but don't feed me a line of @$%@#$# without having something to back it up with.
 

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Well, there is a thing called matched memory. It mandates that the chips are chosen and tested throughly from the exact same fabrication process to test within proper signaling tolerances with each other. It is amazing how much a given batch of memory might differ from the other in terms of actual response, timing or batch signaling. Matched memory is definately preferred option when going to use DDR based memory. While non-matched memory will normally work, there have been many cases of DDR
simply not working or worse damage to MB from bad RAM banks on 1 of the 2 chips. I know ---- QC should be there, but with matched RAM --- it really seems to make a difference. As a BSCE
(computer engineering) major we had major in-depth exploration
into fabrication, design and testing of memory units.

Keep in mind that the memory controller is what makes it 'dual channel' not the processor nor the "memory sticks" ... unless we are talking Athlon64 where the memory controller is in the CPU. To use dual channel the RAM sticks must be the same size and most motherboard manufacturers insist that they should be a matched pair. It was a wise choice to get the matched pair. :)

On a normal dual channel motherboard it usually means there is simply two memory controllers, one managing each of the slots. Most boards have 3 slots though, so often 1 and 2 share a controller and 3 is on its own. This way if you have 2 sticks of RAM that don't match you can put them in slots 1 and 2 and not use dual channel.

Dual channel memory works just like RAID on a HDD. Basically the two memory controllers stripe the data accross/between both sticks of RAM to allow faster access. Functionally in single channel memory the one memory controller just assigns address to the RAM and realistaically sees one 'chunk' of RAM being the sum of all the sticks. In dual channel each controller address its stick of RAM independently and allows each stick to be access simultaneously.

Could this kid explain it? No.

Was it a wise purchase for matched pairs? Yep.

Was it dumb to try to tell someone to buy something when you cannot explain the reasoning behind your recommendation?
Certainly!!!

Well, hope this helps makes your friend feel better about his purchase. It was a wise move --- hopefully not too much more expensive. Sorry you had to deal with BS about "bigger data channel" --- he just couldn't explain it properly. I hope I managed to.

:furious:
 

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Well my opioun on Comp usa?????? I have not step foot in one in over 5 years. I refuse to give them ANY of my money. You go in there, look over, under, and around to find anyone to help. Then you get a usless line of [email protected] from who you talk to. THEN they are out of stock on the sale idem you went in for. After a few years of that "service" I vowed NEVER to go back, and have not.:mad: :mad: :mad:
 

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EX Super Mod
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Well yall lost me with all that high tech talk as long as mine works im a happy camper:D
Jody
 

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Andy,
I actually understood your explaination and I don't know how:D But you actually did teach this old dog somptin' new.
 

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Tractor Lover
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Originally posted by admin
Well, there is a thing called matched memory. It mandates that the chips are chosen and tested throughly from the exact same fabrication process to test within proper signaling tolerances with each other. It is amazing how much a given batch of memory might differ from the other in terms of actual response, timing or batch signaling. Matched memory is definately preferred option when going to use DDR based memory. While non-matched memory will normally work, there have been many cases of DDR
simply not working or worse damage to MB from bad RAM banks on 1 of the 2 chips. I know ---- QC should be there, but with matched RAM --- it really seems to make a difference. As a BSCE
(computer engineering) major we had major in-depth exploration
into fabrication, design and testing of memory units.

Keep in mind that the memory controller is what makes it 'dual channel' not the processor nor the "memory sticks" ... unless we are talking Athlon64 where the memory controller is in the CPU. To use dual channel the RAM sticks must be the same size and most motherboard manufacturers insist that they should be a matched pair. It was a wise choice to get the matched pair. :)

On a normal dual channel motherboard it usually means there is simply two memory controllers, one managing each of the slots. Most boards have 3 slots though, so often 1 and 2 share a controller and 3 is on its own. This way if you have 2 sticks of RAM that don't match you can put them in slots 1 and 2 and not use dual channel.

Dual channel memory works just like RAID on a HDD. Basically the two memory controllers stripe the data accross/between both sticks of RAM to allow faster access. Functionally in single channel memory the one memory controller just assigns address to the RAM and realistaically sees one 'chunk' of RAM being the sum of all the sticks. In dual channel each controller address its stick of RAM independently and allows each stick to be access simultaneously.

Could this kid explain it? No.

Was it a wise purchase for matched pairs? Yep.

Was it dumb to try to tell someone to buy something when you cannot explain the reasoning behind your recommendation?
Certainly!!!

Well, hope this helps makes your friend feel better about his purchase. It was a wise move --- hopefully not too much more expensive. Sorry you had to deal with BS about "bigger data channel" --- he just couldn't explain it properly. I hope I managed to.

:furious:
:dazed: H U H? :dazed:
 

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Premium Member
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800 Posts
Originally posted by admin
Well, there is a thing called matched memory. It mandates that the chips are chosen and tested throughly from the exact same fabrication process to test within proper signaling tolerances with each other. It is amazing how much a given batch of memory might differ from the other in terms of actual response, timing or batch signaling. Matched memory is definately preferred option when going to use DDR based memory. While non-matched memory will normally work, there have been many cases of DDR
simply not working or worse damage to MB from bad RAM banks on 1 of the 2 chips. I know ---- QC should be there, but with matched RAM --- it really seems to make a difference. As a BSCE
(computer engineering) major we had major in-depth exploration
into fabrication, design and testing of memory units.

Keep in mind that the memory controller is what makes it 'dual channel' not the processor nor the "memory sticks" ... unless we are talking Athlon64 where the memory controller is in the CPU. To use dual channel the RAM sticks must be the same size and most motherboard manufacturers insist that they should be a matched pair. It was a wise choice to get the matched pair. :)

On a normal dual channel motherboard it usually means there is simply two memory controllers, one managing each of the slots. Most boards have 3 slots though, so often 1 and 2 share a controller and 3 is on its own. This way if you have 2 sticks of RAM that don't match you can put them in slots 1 and 2 and not use dual channel.

Dual channel memory works just like RAID on a HDD. Basically the two memory controllers stripe the data accross/between both sticks of RAM to allow faster access. Functionally in single channel memory the one memory controller just assigns address to the RAM and realistaically sees one 'chunk' of RAM being the sum of all the sticks. In dual channel each controller address its stick of RAM independently and allows each stick to be access simultaneously.

Could this kid explain it? No.

Was it a wise purchase for matched pairs? Yep.

Was it dumb to try to tell someone to buy something when you cannot explain the reasoning behind your recommendation?
Certainly!!!

Well, hope this helps makes your friend feel better about his purchase. It was a wise move --- hopefully not too much more expensive. Sorry you had to deal with BS about "bigger data channel" --- he just couldn't explain it properly. I hope I managed to.

:furious:
That's exactly what I was thinking!
 

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Ah, the muffler bearings are connected to the kniphela rods, and the flux capacitator must be fluxing to produce the 1.21 gigawatts of power required!!

:dazed:

Sorry I am lost too.....sort of?
 

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i never go to compu USA.. ill go to tiger direct or to a local pc shop... they at least know what they are talking about.. unlike the 16 year olds at comp USA
 

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Premium Member
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I was able to see through the mud Andy. You did good. I remember transistors being available in matched pairs. One use was an audio amplifier push pull circuit. Other wise one transistor may have a higher gain than the other and reduce the efficiency of the circuit causing distortion or reduced output. After reading your explaination, I can see how using memory chips from the same silicon batch or matched through testing would be best.

Mark:)
 

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Premium Member
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Well, with the heavier demands for overclockers and other memory pushing freaks, most good companies like Corsair, OCZ, Crucial etc starting making high quality memory with both less latency, clock cycles/wait states (better chips, leads, dies) then "standard" run of the mill
memory which for the most part was good, but unproven and tested under significant timing load (overclocking and advanced DDR testing) DDR would not always pass the test. It is true that DDR has been around for quite some time but also completely true that matched pairs perform MUCH better than individual sticks that are untested to work together under load.
In fact some memory (depending on sensitivity of the controllers will refuse to operate at ALL on given high quality MBs) if they are not matched. Matched pairs used to cost about 25-50% more per batch than unmatched but it seems that price has dropped significantly to just a few % points on any given sale.

If this is in fact the case, always get matched pairs especially when chosing to build your own PC. It is just not worth the long-term aggrivation and problems you might experience without them --- plus the performance gains associated with true DDR is
very real. :D

Andy
 

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Discussion Starter #16
I understand about the matched memory and testing process, just not sure that was the case here. The guy was cracking me up with the "wider data channel", at that point no matter what he said I was going to poke at him.
 

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Sure it was the case here. He was trying to sell you something he couldn't explain. It is true that DDR does provide a "wider data channel" if you look at the ability of it to handle data in simultaneous format across both controllers and ultimately being able to significantly increase memory data flow. Now, if he could have explained to you that by buying the dual pack that was matched memory pairs, you would been guaranteed full compatibility and maximum speed for just a few dollars more, I am sure that you would have appreciated his insight. :D
He was misinformed. Thinking the memory provided the DDR when in fact it is merely an agent of the process.


Him -> This pack is sold in pairs and is rated to go together. The single packs are not rated together.
Me -> So I need to spend a few more dollars to buy the pack that has two of them in the same package because they came down the assembly line side by side.
Him -> no response.
After he went into the back, he "remembered" why he was saying what he did. (see pairs rated together) Remember that these teenage techs don't work on commission, so while he may not have been very clear with his explanation or reasoning --- he was trying to help your friend make the best possible purchasing decision.

All-in-all, pairs are best. Your friend got the better components
and hopefully is enjoying his new PC! :D

Cheers
:cheers:
 

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Discussion Starter #18
We were look at two DDR PC3200 packs of memory. A set of singles and a pack of two. He pointed to the pack of two and said that this particular DDR has a wider data channel than the other single DDR PC3200. That is why I laughed.

I agree with the pairs, but, just because they are packaged together, doesn't mean they are "paired". I would think that the packaging would reference that in some form or fashion. Most likely... they are. Just like carpet, tile and some other things, it is always better getting things from the same "run".
 

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Yep ----- Would be a lot of laughs!!!! I can certainly see that, Tuba! :D :D :D

What a fool at COMPUSA.....What can you expect sometimes I guess...

:furious: :furious: :furious:
 
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