Dual-channel vs. single RAM

[Jon Hartman]

Time to build a new PC! The ATI 7200 SDR 64MB, the TV Wonder VE, the Sony
DRU-510A, and the ATA133 120GB HD are coming over from the PC, but that
still leaves me with several components to purchase. Well, I'd always
thought the whole "chipset" concern about PC's was a bunch of
smoke-and-mirrors, but recalling a conversation w/a coworker regarding them,
I decided to do a bit more reading. I found this:
http://www.tomshardware.com/motherboard/20020422/ which was quite
educational. Reading that got me to take another look at the RAM:
a.. PC 3200
b.. 3-4-4-8
c.. DDR
d.. 1GB
e.. 400MHz
f.. Single Channel
Single channel? I wanted to know about this, so I went googling once more
and read this: www.kingston.com/newtech/MKF_520DDRwhitepaper.pdf but am
still wondering... Is there something about this RAM that would limit it to
single-channel operation? I would think that as long as the memory
controller supports dual-channel operations, the actual RAM configuration
would be irrelevant, provided it matched what was in the same slot on the
other channel. Am I incorrect?

-Jon

 

[George Macdonald]

Time to build a new PC! The ATI 7200 SDR 64MB, the TV Wonder VE, the Sony
DRU-510A, and the ATA133 120GB HD are coming over from the PC, but that
still leaves me with several components to purchase. Well, I'd always
thought the whole "chipset" concern about PC's was a bunch of
smoke-and-mirrors, but recalling a conversation w/a coworker regarding them,
I decided to do a bit more reading. I found this:
http://www.tomshardware.com/motherboard/20020422/ which was quite
educational.

That's an old article and doesn't bear much relevance to current chipsets
or mbrds.

Reading that got me to take another look at the RAM:
a.. PC 3200
b.. 3-4-4-8
c.. DDR
d.. 1GB
e.. 400MHz
f.. Single Channel
Single channel? I wanted to know about this, so I went googling once more
and read this: www.kingston.com/newtech/MKF_520DDRwhitepaper.pdf but am
still wondering... Is there something about this RAM that would limit it to
single-channel operation? I would think that as long as the memory
controller supports dual-channel operations, the actual RAM configuration
would be irrelevant, provided it matched what was in the same slot on the
other channel. Am I incorrect?

Which "RAM" are you talking about? Is it a specific PC3200 DIMM you're
referring to... made by whom? With the proviso of good quality, sure you
can take two separate but identical DIMMs and run them dual channel - the
matched pair thing is just a marketing ploy and partially to protect from
dumbos who buy unmatched separates and then whinge when they don't work.

One thing to watch in modern systems is the rank count, i.e. the number of
populated DIMM sides (what used to be called banks) - keeping that down
helps allow higher speed operation and the possibiliy of adding later
without losing speed. In that respect 512Mb chips are an advantage. IMO
this DIMM: http://www.newegg.com/Product/Product.asp?Item=N82E16820146541
is one of the best buys around: it's made by Crucial/Micron, it uses 512Mb
chips so is "single sided" 8 chips and is 3-3-3-8. I've used it in three
recent builds with Athlon64 3500+, it works perfectly in dual channel s939
set up and it works with "1T" command rate - Sandra bandwidth is just a
hair short of 6GB/s. 1GB for $83.+s&h at that performance is a real
bargain. Oh, before you ask, I don't overclock.

 

[Gnu_Raiz]

That's an old article and doesn't bear much relevance to current chipsets
or mbrds.


Which "RAM" are you talking about? Is it a specific PC3200 DIMM you're
referring to... made by whom? With the proviso of good quality, sure you
can take two separate but identical DIMMs and run them dual channel - the
matched pair thing is just a marketing ploy and partially to protect from
dumbos who buy unmatched separates and then whinge when they don't work.

One thing to watch in modern systems is the rank count, i.e. the number of
populated DIMM sides (what used to be called banks) - keeping that down
helps allow higher speed operation and the possibiliy of adding later
without losing speed. In that respect 512Mb chips are an advantage. IMO
this DIMM: http://www.newegg.com/Product/Product.asp?Item=N82E16820146541
is one of the best buys around: it's made by Crucial/Micron, it uses 512Mb
chips so is "single sided" 8 chips and is 3-3-3-8. I've used it in three
recent builds with Athlon64 3500+, it works perfectly in dual channel s939
set up and it works with "1T" command rate - Sandra bandwidth is just a
hair short of 6GB/s. 1GB for $83.+s&h at that performance is a real
bargain. Oh, before you ask, I don't overclock.

I read that as Oh No, another tomshardware qoute thread. In these parts
those are fighting words, anything with tom and hardware in the same
sentence is like a red flag, kind of like Intel and AMD in the same
subject line.

I agree a good stick of 1 gb memory should not cost more than 100 bucks.
If your a game player you might want to consider a single stick instead of
dual 512 sticks, as games such as bf2 love memory. As far as matching
sticks of memory, that has been hashed out before. Now if you have dual
channel memory then you will want to go with two sticks, otherwise a
single stick will be fine.

As far as matched sticks are concerned its a good choice to stick to name
brand of the same type of memory. Its debatable as to what matching means
from the manufacture, some think its from the same batch, some think think
its from the same speed bin, some think its matched because its in the
same package. Only the manufacture will really know exactly what matching
means, but if you stick to the same brand, and speed you should be fine.

For example say you but two 1 gb's sticks from crucial, then in the future
you want to add another 2 gb's, it would be advisable to buy from crucial
again the same speed as before. Now its possible to mix and match, say you
have kingston, and crucial or any name brand, if its the right speed
everything might work out fine, but people have had problems. Your
experience might vary, but common sense usually works pretty well.

Gnu_Raiz

 

[dawg]

Single and dual channel is a function of the motherboard or cpu(AMD64/onchip
mem controller).
But to use dual channel you should have two modules of the same
specs,manufacturer,speed and capacity. They don't have to be sold as a
"set".