# what does single sided and double sided memory mean?



## ny_driver (Jan 1, 2007)

And I don't really understand the table about suggested module combinations? Is the board going to read my ram as dual channel...or what?

http://www.msicomputer.com/product/p_spec.asp?model=K8T_Neo2-F&class=mb

Do I put 1 stick in Dimm 2 and 1 stick in Dimm 4?


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## Yin (Jan 1, 2007)

I think its both in the green or purple dims, for dual channel so either green or purple.
when it starts up it'll say if its dual channel or not


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## ny_driver (Jan 1, 2007)

this is the RAM I have . How can I tell if single sided. Or is most modern decent RAM going to be single sided?

http://www.crucial.com/store/partspecs.Asp?IMODULE=BL2KIT6464Z402

That is not where I bought it! I think I paid $120 or less


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## tkpenalty (Jan 2, 2007)

Omg.... geez.... Guys...

Single Sided RAM Is basically just the Ram modules mounted only on one side of the stick.
Double Sided RAM Is similar just that the RAM Modules are mounted on both sides.
Single sided RAM normally cannot exceed 512MB Whereas Double Sided RAM normally cannot exceed 1GB. 
Usually 1GB Sticks are Double sided, as well as 512MB sticks.
Single Sided RAM Modules are thinner by a 1mm and there is one side of the PCB which has no modules mounted on.
However with the newer 2GB Double sided sticks, there may as well be 1GB single sided RAM Modules.
Either way, single sided and double sided wont even give you a hunch on how the RAM is going to perform >_>.

Dual Channel is DIFFERENT, Nothing to do with the physical attribute of the Stick itself. Dual Channel RAM bascially is when two Modules are mounted in two keyed by colour RAM Slots. Usually they are seperated by a small gap.They Must be mounted like this.

Slot 1: [DDRII Kingston 512MB]
Slot 2: [Empty---------------]

Slot 3: [DDRII Kingston 512MB]
Slot 4: [Empty---------------]

The pairs MUST be identical. The Red slots can be populated with another pair of RAM modules which have to be identical as well, however not with the blue slots.
Usually when buying RAM you must consider what motherboard you are using, for example if your motherboard does not support dual channel, it is better off buying just one single stick of 1GB, if it does two 512MB are better.


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## tkpenalty (Jan 2, 2007)

ny_driver said:


> this is the RAM I have . How can I tell if single sided. Or is most modern decent RAM going to be single sided?
> 
> http://www.crucial.com/store/partspecs.Asp?IMODULE=BL2KIT6464Z402
> 
> That is not where I bought it! I think I paid $120 or less



Doesn't matter anyway  . Its probably double sided, as if single sided makes RAM three times better.


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## Yin (Jan 2, 2007)

I wasn't into computers when this single sided ram was around, when i started ddr was the standard


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## ny_driver (Jan 2, 2007)

Thank you very much for the detailed explanation But are you sure about the slots to populate? It looks to me like if I have 2 sticks of 512 and I want them to work in dual channel I would put them in Dimm2 and Dimm4. The only time I would populate Dimm1 and Dimm3 is if I have 4 sticks of ram. Am I reading that correctly?


http://www.msicomputer.com/product/p_spec.asp?model=K8T_Neo2-F&class=mb


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## francis511 (Jan 2, 2007)

i read somewhere that double-sided ram gives a slight performance boost
over single-sided.


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## ny_driver (Jan 2, 2007)

francis511 said:


> i read somewhere that double-sided ram gives a slight performance boost
> over single-sided.



Hmmmm...I thought I read the opposite like right here....and I quote,,

When referring to RAM modules, the terms take on a less literal meaning. "Single sided" refers to a RAM expansion with a single "bank" of chips, which the computer can access all at once. The physical expansion card may have chips on both of its sides, or only on one side, but is considered to be single sided because the computer can "see" all of its memory at once.

"Double sided" RAM has its chips divided into two sides (called "banks"), only one of which can be seen at a time by the computer. Initially, these were created by essentially attaching two single-sided SIMM cards to the same PCB, but more modern chips use different wiring. Pins 33 and 45 on the board are used by double-sided memory, and can sometimes be an indicator as to whether a given module is single or double-sided. To use the second half of the storage available, the computer must switch to the second bank, and can no longer read or write to the first half until it switches back again.

Higher-end computer systems may wish to avoid using double-sided memory because of the reduced performance that results from the time needed to switch banks, however it is not a noticeable decrease for the majority of personal uses.
Retrieved from "http://en.wikipedia.org/wiki/Single_sided/double_sided"


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## francis511 (Jan 2, 2007)

ny_driver said:


> Hmmmm...I thought I read the opposite like right here....and I quote,,
> 
> When referring to RAM modules, the terms take on a less literal meaning. "Single sided" refers to a RAM expansion with a single "bank" of chips, which the computer can access all at once. The physical expansion card may have chips on both of its sides, or only on one side, but is considered to be single sided because the computer can "see" all of its memory at once.
> 
> ...



im sure it was teh other way round. damn -if i could just remember where i saw it!


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## francis511 (Jan 2, 2007)

DING 100 posts


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## SqueezeR (Jan 2, 2007)

hi ny_driver,
you can find something TWICE interesting here:

www.planetamd64.com/lofiversion/index.php/t16298.html

In order to benefit of the dual channel functionality put the two ram sticks (btw, they're double sided, ehehehe) in slot 2 and 4 (just as you said) and they will work at full 400MHz.
The limitation of 4 sticks running at 333MHz instead of 400MHz is due to the Athlon's integrated memory controller, but most mobos (included your MSI i suppose) can be "forced" to let it run at full throttle


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## ny_driver (Jan 2, 2007)

Thanks for the info Squeezer. I think the table you referred to is for a different MSI board because it is different that the one I originally referred to....maybe it is too early and I am confused.

that table tells me to put them in either Dimm1 and Dimm2 or Dimm3 and Dimm4 with only 2 sticks dual channel, unless I wanted to run it at 333mHz.

http://homepages.nildram.co.uk/~chsmith/7125_Neo4_Memory.pdf


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## largon (Jan 2, 2007)

Single and double sided DIMMs can't be differentiated from each other by the count or placement of the chips. The type and internal structure of the chip is the only thing that matter. 

Single sided dimm
1. is a 64bit wide group of chips by definition
2. has 1 rank (1 rank is the 64bit group mentioned earlier)
3. can have chips on both sides of the stick
4. easier for the memory controller (theoretically overclocks higher than double sided)
5. no rank interleave -> slight performance loss
6. rank is always "open" -> slightly less latency
7. has no "maximum" capacity 
8. capacity depends on density of the DRAM chip (32x8 -> 512Mbit/IC, 64x8 -> 1Gbit/IC, 128x8 -> 2Gbit/IC, and on and on...)

Double sided dimm
1. is a 128bit wide group of chips = 2 ranks 
2. can have chips just on 1 side of the dimm (if the chips used are built in 16 arrays = 16*x16* -> 256Mbit/IC, )
3. is more stressing for the memory controller (OCs less)
4. can do 2-rank / 4-rank interleave when 2 / 4 sticks are installed -> perf increase


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## ny_driver (Jan 3, 2007)

huh...alot of information for me to absorb, but thank you


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## SqueezeR (Jan 3, 2007)

ny_driver said:


> Thanks for the info Squeezer. I think the table you referred to is for a different MSI board because it is different that the one I originally referred to....maybe it is too early and I am confused.



Sorry for the misreading m8, I took for granted you were talking about the newer Neo4... sort of an automatic selector inside my head  
I hope the "single side/double side" stuff was useful btw


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## ny_driver (Jan 3, 2007)

I know alot more about it today than I did yesterday.


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