Dual Channel Single DIMM

[NoStateofMind]

IDK if this has been thought of, implemented or discarded as an idea but I wanted to share it with you guys to see if its possible or if its worth anything.

I started thinking about RAM and how two sticks can work in tandem for "dual channel". Then I thought, well why not dual channel on one stick? Triple channel on one stick? Quad? The possibilities are endless. Here's my crude drawing in paint to give you an idea of what I mean:

http://i681.photobucket.com/al...lchannelsingledimm.jpg

The RAM chips would be separated on one DIMM, one for channel one the other for channel two. Separated by spaces in the "teeth" for voltages/data transfers. I'm thinking it would need some sort of "Data Regulation" chips like the x58 boards have for their triple channel. IDK, just tossing it out at you guys. What do you think?

 

[Billb2]

And why would we be doing this?

 

[NoStateofMind]

Originally posted by: Billb2
And why would we be doing this?

Increased bandwidth and possibly speed as well. Space requirements. Able to shrink motherboard sizes and keep performance (think SFF or netbooks) or increase performance for higher end systems. Triple bandwidth boards like x58 would end up being sextuplet bandwidth etc.

 

[lopri]

It's definitely possible to my knowledge. Whether JEDEC will approve such specs, that I am not sure.

 

[tcsenter]

Originally posted by: PC Surgeon
What do you think?

I think you just illustrated the dual rank DIMM.

 

[Idontcare]

It's a cool idea. Off the top of my head I would guess the sole reason it is not done is because of trace density versus PCB layers.

It's challenging enough getting the traces to the dimm to handle a single dimms worth of dataflow (pin count).

To go and double the pin-count (effectively your proposal) or triple it would require drastic changes in PCB layout (with all the accompanying added costs of design, validation, and manufacturing) to handle all that signal lines.

But IF it were to be done then you'd want to vertically tier the DIMM and pinouts, not make it just longer in the horizontal direction, if space-savings on the board are of interest. (requiring the DIMM PCB itself to become multi-layer)

 

[NoStateofMind]

Originally posted by: Idontcare
It's a cool idea. Off the top of my head I would guess the sole reason it is not done is because of trace density versus PCB layers.

It's challenging enough getting the traces to the dimm to handle a single dimms worth of dataflow (pin count).

To go and double the pin-count (effectively your proposal) or triple it would require drastic changes in PCB layout (with all the accompanying added costs of design, validation, and manufacturing) to handle all that signal lines.

But IF it were to be done then you'd want to vertically tier the DIMM and pinouts, not make it just longer in the horizontal direction, if space-savings on the board are of interest. (requiring the DIMM PCB itself to become multi-layer)

Well look at 200pin SODIMM's in laptops. Putting two of them together length wise would make them relatively the same length as a normal 240pin DDR2/DDR3 DIMM so I think it can be done with not too much effort. That's basically the idea I'm proposing.

 

[MrPickins]

So you want 400+ pin DIMMs with double the bus width?

It may happen, but not anytime soon, I'd wager.

 

[Idontcare]

Originally posted by: MrPickins
So you want 400+ pin DIMMs with double the bus width?

It may happen, but not anytime soon, I'd wager.

You forgot to add the "for same or lower cost" caveat. That's the only reason it isn't happening today, there are no technological impediments to creating 5,000 pin dimms, cost (and resultant projected lack of demand) is the only impediment.

 

[ElBurro]

So basically your saying put 2 DIMM slots in a line instead of next to each other. I don't see why not but I not sure what the advantage that would provide over having them as they are.

 

[NoStateofMind]

Originally posted by: ElBurro
So basically your saying put 2 DIMM slots in a line instead of next to each other. I don't see why not but I not sure what the advantage that would provide over having them as they are.

Dual channel one slot.

 

[Idontcare]

Originally posted by: PC Surgeon

Originally posted by: ElBurro
So basically your saying put 2 DIMM slots in a line instead of next to each other. I don't see why not but I not sure what the advantage that would provide over having them as they are.

Dual channel one slot.

What advantage would this offer over a dual channel two slot configuration using traditional so-dimms?

 

[Itchrelief]

QIMM?

 

[NoStateofMind]

Originally posted by: Idontcare

Originally posted by: PC Surgeon

Originally posted by: ElBurro
So basically your saying put 2 DIMM slots in a line instead of next to each other. I don't see why not but I not sure what the advantage that would provide over having them as they are.

Dual channel one slot.

What advantage would this offer over a dual channel two slot configuration using traditional so-dimms?

Smaller size, more bandwidth per slot. The above use of 2x200pin SODIMM's was only to give an example. That may work for one slot on a desktop motherboard but the normal SODIMM's for laptops/netbooks would need some sort of divider.

 

[MrPickins]

Originally posted by: PC Surgeon

Originally posted by: Idontcare

Originally posted by: PC Surgeon

Originally posted by: ElBurro
So basically your saying put 2 DIMM slots in a line instead of next to each other. I don't see why not but I not sure what the advantage that would provide over having them as they are.

Dual channel one slot.

What advantage would this offer over a dual channel two slot configuration using traditional so-dimms?

Smaller size, more bandwidth per slot. The above use of 2x200pin SODIMM's was only to give an example. That may work for one slot on a desktop motherboard but the normal SODIMM's for laptops/netbooks would need some sort of divider.

As others have said, routing that many traces on the motherboards would be a nightmare. Increasing bus width sounds nice, but you never get a free lunch.

 

[hans007]

seeing as they actually make double sided and single sided dimms, the double sided ones you'd theoretically be able to do this with if they had a standard for it.