Posted on 03/19/2008 5:50:28 PM PDT by LouAvul
I'm going to order a Dell laptop Latitude computer. The specs say:
[i]2.0GB, DDR2-667 SDRAM, 2 DIMMS [Included in Price][/i]
Now, "DIMM" is "Dual Inline Memory Module," right? That means it has two sockets for the memory strips?
But it offers, as a $30 option, 2 GB memory with 1 DIMM. I thought DIMM required memory be installed in pairs.
Why is this better?
thanx
Pay whatever it takes to get the maximum amount of ram you can possibly get in it.
what’s the max memory? if there is an extra slot you can always add more
Get 20 gigs memory (get the max)
It’s better to run RAM in pairs. That way, the RAM will run in, what is called “dual-channel” mode, and you’ll get a small performance improvement over “single-channel” mode.
http://en.wikipedia.org/wiki/Dual_channel
Pay the $30 more to get the single SODIMM. You want that extra slot.
Otherwise, when you go to upgrade RAM, you have to take out some existing RAM to install more. What I think they’re doing is two slots: 1gb + 1gb or, for $30 more, two slots, 2gb + 0gb.
If you want to add RAM later, it goes in one of those slots.
Ideally, buy the maximum RAM you can get right now. But if not, at least pay the extra for the dense single stick (and the empty second slot).
With 1 2GB module you could upgrade by buying another 2GB module for the other slot to make 4 GB.
With 2 1 GB modules you would have to remove or or two 1 GB modules in order to upgrade to 3 GB or 4 GB.
Some people may think it’s a waste of the 1 GB chips, some may have other uses for them.
I do not know the answer too your question yet will ping someone who will........and bump the thread too the top !
Remember there is always the gorilla tape option !!
Read the thing in #5, pay the extra for 4 gigs (and use only 3.5 gigs in a 32 bit OS).
No Dual means the memory is double sided and uses double the bandwidth. I would personally stick with the two 1 gb dimm’s as you will receive a litle more pop from it than using one big DIMM, alternatively take the 2 gb single stick and upgrade later to have more memory.
Using one slot will be marginally slower, but you can easily add another stick of memory without having to trash some of the memory you bought with the machine. That’s probably worth the $30.
Just remember that 3 gigs is the effective max for 32bit operating systems, so even if you add 2 more gigs, your computer will only be able to access a little more than 3 gigs.
32 bit operating systems can access 4 gigs of address space, but need to reserve some of that memory space for system functions like video and BIOS. It is the same issue as the 640k limit in DOS.
So an upgrade would mean going from 2 gig RAM to 4 gig RAM. All I need the computer for is powerpoint real estate presentations, word processing, excel and watching netflix. Do I really need 4 gigs RAM?
No, the word “Dual” in “dual inline memory module” refers to the fact that the edge pads on the top of the stick are different from the edge pads in the same place on the bottom of the stick.
The old SIMMS (single inline memory module) have edge pads on the top and the bottom, and edge pads on top of the PCB line up with edge pads on the bottom and are the same signal, effectively giving you half the connections you can get with a DIMM.
Gotta be careful...not a lot of laptops support dual channel. You have to have that in the chipset, and dual-channel isn’t necessarily conducive to low-power operation.
My bet is that:
a) Your laptop doesn’t support dual-channel (i.e. you get no speed increase from using 2 dimms that are identical)
and
b) Your OS can’t use more than 3GB because of what MediaMole said.
Therefore, if you put 4GB in there, you are getting 3GB of memory and spending the money and battery power to refresh an extra 1GB of DRAM that you are never using.
As long as there you feel comfortable that you get nothing from using dual-channel, there is no reason to get 4GB instead of 3GB, and your battery will last a little longer as a result.
If I were you, I’d spend the $30 to get your 2GB as one DIMM, then buy a 1GB DIMM later if you see you need it.
Do not spend the joules of energy refreshing DRAM that you can’t use! (which would happen if you had a total of 4GB)
Probably not. I use 512MB and it's pretty fast.
Somewhere it should tell you how much RAM is supported in the system. It sounds as if the system supports at least 4GB of RAM, as in 2 x 2GB modules, though it could support more...
But that brings up a number of other questions: What processor and OS will it be using. If you’re using a 32 bit processor or OS, the maximum amount of RAM that can be addressed is 4GB, though due to system overhead, you’ll probably only see 3.5GB - 3.75GB total. That’s because devices like the system BIOS and video adapters “intrude” into that 4GB address space, keeping your computer from being able to access all 4GB. However, if you have a 64 bit processor, hardware designed for 64bit operation, and 64 bit OS, then the system can address far more RAM.
Finally depending on the design of the system, if you install the RAM in pairs, you may see improved performance, but that’s not always the case.
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