Is Laptop RAM Inherently Inferior to Desktop RAM?

[bobross419]

With its smaller size and the increase in PCIe slots and RAM slots on high end motherboards, it makes me wonder if there is a reason why Mobo manufacturers aren't switching to the smaller laptop memory. It seems that with smaller memory they could cram more stuff onto a motherboard, or just install better NB/SB heatsinks and such. Just popped into my head and figured I'd ask the AT Gurus

 

[Hacp]

There are standards. Ultimately, you could solder the ran to the PCB to save the most space, but that's not how the ram makes sell them.

 

[nipplefish]

That didn't really answer the question... he was asking why they don't use SODIMM as the standard for desktop boards to create space for additional features. It's actually a pretty good question. Are SODIMMs inherantly slower than DIMMs? Some other disadvantage?

6 DIMMs on an X58 takes up a pretty good chunk of space... you could add more SATA ports or something if it used SODIMMs instead.

 

[aka1nas]

I don't think I have ever seen a SO-DIMM with 16 DRAM chips on it. That means they have to use denser and more expensive chips to generate the same capacity.

 

[Meghan54]

So, what exactly is missing from your motherboards that smaller RAM slots would help make the "missing" stuff fit?

 

[CurseTheSky]

So, what exactly is missing from your motherboards that smaller RAM slots would help make the "missing" stuff fit?

Better board layouts, additional space so it's not difficult (on some boards) to remove the CMOS battery, POST LEDs / LCDs, power / reset / BIOS reset buttons, etc.

Most of these are niceties, but they would be great to have if possible. I realize some boards already come with these features, but there are still plenty that don't.

 

[Absolution75]

I assume they cost more - trying to cram 4GB on a SO-DIMM stick is a lot tougher than on a regular DIMM.

 

[Rifter]

this is a bad idea, laptop ram is more expensive. and space is not an issue for desktop boards.

 

[taltamir]

sodimms are physically smaller, therefore they require greater miniaturization, making them more expensive.
or at least, that used to be the case. Density seems to have hit a brick wall; sodimms manage to carefully arrange the same 8 chips on a smaller area, and prices for sodimms seem to be the same as full sized ram. (based on newegg prices for single 2GB and single 4GB ram sticks)

 

[nipplefish]

Yeah, I was about to say the same thing... the miniaturization argument seems logical, but current SODIMM prices and capacities don't support it.

 

[RebateMonger]

I think the miniaturization argument still makes sense. But these are commodity items so other factors (such as supply/demand) also have weight.

Historically, SODIMMS have had more compatibility problems than desktop memory. That was definitely an issue before DDR2 memory. For instance, while PC66, PC100, and PC133 memory was generally interchangeable on desktops, there were laptops where they weren't. And my 2005 DDR1 Toshiba laptop would generate 1000s of errors per hour with some brands of SODIMMS. I don't know if the compatibility problem was with laptop design or the memory modules themselves.

I haven't read of memory compatibility issues with DDR2 or DDR3 laptop memory.

 

[aka1nas]

sodimms are physically smaller, therefore they require greater miniaturization, making them more expensive.
or at least, that used to be the case. Density seems to have hit a brick wall; sodimms manage to carefully arrange the same 8 chips on a smaller area, and prices for sodimms seem to be the same as full sized ram. (based on newegg prices for single 2GB and single 4GB ram sticks)

Most high capacity desktop modules use 16 chips still.

The 64-bit transition is still biting us in the ass, and we're in a chicken/egg scenario of developers writing more 64-bit programs that use more memory and hardware vendors producing denser commodity modules.

 

[bobross419]

The price posts aren't really an issue, since prices are so close as it is now. As far as space, there are plenty of boards out there where people run into physical issues when installing a big heatsink or something. We could also see benefits in airflow by using SODIMM (thanks for giving me the correct term for the laptop RAM) that has a smaller surface area than the DIMM standard.

Possible compatibility issues could be a culprit. I don't know much about incompatibility issues with laptop memory, but I'm sure mobo manufacturers might have some better information.

Even if this wasn't something done on full ATX or bigger boards, I'm still not sure why we haven't see more of this on the smaller boards. Even on the Mini-ITX boards, only 2 out of the 12 Intel Mini-ITX available on Newegg utilize the 2x200 pin SODIMM -- And these are both Socket P (Which is a "laptop" processor); On the AMD side we have 1 in 4 Mini-ITX with SODIMM. Looking through Mini-box.com's Atoms listing shows a similar trend. With something as small as Mini-ITX, I'm quite surprised at the lack of available motherboards utilizing the smaller modules.

Could it be that motherboard manufacturer's assume that consumers won't like the idea of being forced to use laptop RAM? Is it more expensive to put in the hardware for SODIMM?

 

[Jd007]

The issue used to be price. SO-DIMMs cost more to produce than DIMMs, so in desktops where space wasn't a big concern, the cheaper, larger DIMMs were used.

Even though (as someone mentioned above) the price of the two are pretty much the same now, it's become more of an accepted standard. No manufacturer would produce desktop motherboards that used SO-DIMMs, because people are used to putting full-sized DIMMs in their desktop motherboards.

From a purely technical point of view, SO-DIMM and DIMM shouldn't have much, if any, performance differences, as the RAM chips used are the same in both. The pin-count difference shouldn't matter too much at all since that's hardly the bottleneck in memory access.

 

[SunnyD]

The larger desktop modules are somewhat more durable, particularly in terms of the socket. The smaller SODIMMs are indeed inherently inferior, at least in the respect of heat dissipation, which will cause more failures in the long run. Other than that, there is no real reason other than standards.

 

[RebateMonger]

The MSI Wind "nettop" (Atom-based, custom tiny motherboard) uses a single SODIMM memory slot. I believe the Acer nettop (Revo) uses SODIMMs, too.

 

[pitz]

As other posters have said, its simply a cost thing. An extra $40/system *is* a big deal to system builders who build millions of units at a time. I also believe that the SODIMM standard omits ECC capability, doesn't support registers, etc., so there are other issues that thus arise.

 

[bobross419]

As other posters have said, its simply a cost thing. An extra $40/system *is* a big deal to system builders who build millions of units at a time. I also believe that the SODIMM standard omits ECC capability, doesn't support registers, etc., so there are other issues that thus arise.

DIMM 1066 DDR3 2GB
SODIMM 1066 DDR3 2GB

DIMM 1333 DDR3 2GB
SODIMM 1333 DDR3 2GB

DIMM 1600 DDR3 2x2GB
SODIMM 1600 DDR3 2x2GB

It isn't until the 1600 stuff that the prices actually become different, and with 1066, the SODIMMs are actually cheaper (Keep in mind when looking at the 1600, that a lot of the DIMM items are prices after rebate, so it isn't as bad as it looks - Still cheaper, just not as bad as it first appears).

I just did a quick visual check, but I made sure that the CAS Latency and Voltages were comparable. I also checked and everything in all links are both un-Registered and non-ECC. Not to mention that most users don't ever worry about Registered/ECC RAM unless it is in a server environment.

Some of the big deal system builders are already utilizing the SODIMMs in their SFF and/or USFF machines.