Dell laptop dual channel 3 GB RAM?

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Fuzzy33

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Dell Inspiron 1520 and 1720 laptops can now be ordered with 3 GB of RAM in USA and Canada.

That sounds appealing, provided it works in dual channel, but their website provides no credible info about that.

A Dell chat rep said the 3 GB was set up as 1.5+1.5 GB, but I am suspicious of this as I have never heard of 1.5 GB SODIMM's.

On the other hand, a Dell Canada chat rep said the 3 GB was set up as 1+1+1+0. I am suspicious of this because I thought the 1520 and 1720 laptops only had 2 SODIMM's. Also, the price they charge to upgrade from 2 to 3 Gb is twice what they charge to upgrade from 1 to 2 GB; so it sounds like the upgrade is not linear.

So, I would appreciate your help. Do any of you have Dell Inspirons that came with 3 GB? If so, how was it configured?

Does anybody know how many SODIMM slots the 1520 and 1720 have?

Fuzzy
 
Fuzzy33 said:
Does anybody know how many SODIMM slots the 1520 and 1720 have?

Fuzzy
Click to expand...

That's the question you want answered the most.

If it has four, it would be 2 1GB sticks and 2 512 sticks. But if it's only two, then 3GB dual channel is not possible.
 
Service manual only suggests 2 slots: http://support.dell.com/support/edoc....htm#wp1180190

So it's probably 2GB+1GB. Which would also account for the price hike as 2GB sticks look to be a fair bit more expensive than 1GB sticks (newegg).
Click to expand...

My C90 runs a 2 gig and a 1 gig in asymmetrical dual channel.
http://www.asus.com/products.aspx?l1...41&modelmenu=2

Main Memory 2 SO-DIMM Sockets for Expansion Up to 3GB.
Support up to 3GB Dual Channel DDRII 800MHz SDRAM
Click to expand...

Thanks SirHarlock, Tekara and Kettchxxii. That's very helpful, though in the end it is still unclear whether the 3 Gb would be dual channel.

It looks like the 1520 has 2 SODIMM's, but that does not entirely exclude the possibility of dual channel (e.g. the Asus). The US configurator says dual-channel for all memory sizes:
http://configure.us.dell.com/dellstore/config.aspx?c=us&cs=19&l=en&oc=DNCWKA1&s=dhs
while the Canadian configurator says "dual channel" and "2 DIMMS" for all sizes except 3GB.
http://configure.dell.com/dellstore/config.aspx?c=ca&CS=cadhs1&l=en&OC=N15202V_R_E

So, do you think it would be 3 dual channel in Canada? Does it matter?

Fuzzy
 
I don't know of any 3GB sicks so I'm pretty sure it would be have to be two sticks which would make it dual channel.
 
Perhaps laptops are different, but I understood that in order to achieve dual channel, both stick have to be the same size. Since the laptop only has two, a 3GB setup would be a 2GB and a 1GB stick, which should mean single channel.
 
No no, dual channel just means that there are two memory controllers; there is no requirement to have the sticks be the same size.
 
Tekara said:
No no, dual channel just means that there are two memory controllers; there is no requirement to have the sticks be the same size.
Click to expand...

Then why is it that when you put a 256 stick together and a 512 stick together, you get single channel? Or why is it that if you have a single-sided 256 stick with a double-sided 256 stick, you get single channel? Or are desktops and laptops different in this respect?
 
SirHarlock said:
Perhaps laptops are different, but I understood that in order to achieve dual channel, both stick have to be the same size. Since the laptop only has two, a 3GB setup would be a 2GB and a 1GB stick, which should mean single channel.
Click to expand...

I have also understood that operate as dual channel, the sticks have to be of the same capacity. Otherwise, the system runs as single channel.
 
No problems running dual channel on my desktop with 1GB+512MB sticks.

and
Kettchxxii said:
My C90 runs a 2 gig and a 1 gig in asymmetrical dual channel.

http://www.asus.com/products.aspx?l1=5&l2=141&l3=536&l4=0&model=1641&modelmenu=2

Main Memory 2 SO-DIMM Sockets for Expansion Up to 3GB.
Support up to 3GB Dual Channel DDRII 800MHz SDRAM​


/flame on.
Click to expand...

Isn't having any problems either.

I think it's the marketing of matched ram sticks and possibly a few chipsets that has caused the whole belief that the sticks have to be equal. Intel "reinvented" the concept and markets it as flex memory technology and I know AMD has a similar gimmick.
 
Tekara said:
No problems running dual channel on my desktop with 1GB+512MB sticks.

and


Isn't having any problems either.

I think it's the marketing of matched ram sticks and possibly a few chipsets that has caused the whole belief that the sticks have to be equal. Intel "reinvented" the concept and markets it as flex memory technology and I know AMD has a similar gimmick.
Click to expand...

Hmm, well I know my 865PE will only do dual channel if two corresponding slots are filled by two sticks the same size and density.
 
My understanding from a Tomshardware article is that dual channel does not provide noticeable difference vs. single channel when you're talking about 2GB of ram or more. I currently have 1+ 2GB = 3GB total. All the notebooks I have come across only have 2 slots and never 3 or more. so I'm confident to say that that Dell model the OP was talking about would be 1 + 2. And there is no 1.5 or 3GB sticks out there, at least not publicly.
 
Not sure what that means but OK.

I'm running with 1 + 2GB for a total of 3GB on dual channel right now and I notice no difference vs. running 1 x 2GB on single channel. So unless you're the type of person who gets off on running benchmarks all day, no, for your purpose, there is no difference.
 
I am pretty sure this was already answered by Tekara, but the systems that are being sold as having 3 GB of memory in Dual Channel are using "Flex Mode". This allows the systems to have 3 GB (2 GB + 1 GB) or 1.5 GB (1 GB + 512 MB) and still be in Dual Channel. As for the notebooks mentioned here they only have 2 slots for memory.

Here is a link on Intel's website explaining "Flex Mode"

http://www.intel.com/support/motherboards/desktop/sb/cs-011965.htm

I realize this link is for desktops but the same technology is in notebooks as well.

Brad
Dell Customer Advocate
 
If you notice, that Intel article shows 256MB less than they intended - is that a detractor from Flex Mode, or does that indicate shared memory due to a video card onboard?
 
mwarps this appears to be a typo as it should be 512 MB instead of 256 MB. The only thing to be aware of about Flex Mode is that only some of the memory will be in Dual channel. The BIOS will register it in Dual channel, but on 1.5 GB only 1 GB will be in Dual Channel and on 3 GB only 2 GB will be in Dual Channel. Please let me know if you have any more questions.

Brad
Dell Customer Advocate
 
Flex just means that parts that can be dual channel is dual while the rest is single. Dual channel does require matched sizes, but there's no reason the excess on the other chip can't be used...
 
ChronoReverse I believe we are on the same page with this. What I meant in saying "on 3 GB only 2 GB will be in Dual Channel" is that the remaining memory will be in single channel. The Intel link also explains this. Sorry if my last posted added confusion. I basically just wanted to point out the typo on the graphic explaining Flex Mode for mwarps.

Brad
Dell Customer Advocate
 
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