Best Memory Configuration - 2 x 1 or 1 x 2

[Smurfjet]

Greetings,

I'm upgrading the current memory of my laptop from 1 GB to 2 GB.

Right now I have 2 x 512 MB installed for a total of 1 GB. I 'heard' (still trying to find if its true) that running 2 memory sticks of the same size is better (faster?) than one memory stick of combined size. Is this true?

According to the manual my slots will support any configuration, but it does not mention anything about optimal configuration.

Thank you.

[Bushfiva]

If the motherboard supports dual channel memory, then yes, all things being equal, it should be faster since the memory path is 128 bits wide rather than 64 bits wide. In reality, you'll get anything from zero benefit to some benefit. The memory sticks have to be pretty much identical for dual channel to be enabled, which in practice means buying them at the same time. 1GB operating as dual channel probably won't be as useful as, say, more than 1GB of non-dual channel memory.

[Jhieminga]

I think the clue is in the word 'laptop'. Unless you've got a laptop which has more than one expansion memory slot I seriously doubt if it will support dual channel memory. On desktop PCs you'll find four or more memory slots on the motherboard and using similar sticks of memory in two or four slots enables the use of dual channel memory configurations (if supported). On a laptop there is the built-in memory and generally one expansion slot for one SO-DIMM memory stick. As most laptops are never fitted with extra memory there's not much gain in providing dual channel support.

From your description you've got two memory modules installed already? How many memory slots are there in your laptop then?

[Bushfiva]

Most notebooks that claim to have one memory expansion slot actually have two, though the second one may be inaccessible under normal circumstances. But if you're happy disassembling the notebook, the second slot will be the same electrical distance, and roughly the same physical distance, from the memory controller as the visible expansion slot. In practical terms, this means if the visible slot is accessed by a cover underneath the computer, the hidden slot may be on the other side of the motherboard, i.e. under the keyboard. It's always worth poking around. After backing up, of course.

[Smurfjet]

Greetings,

The laptop is an Aspire 5580. It has 2 slots, and 0 base memory. Meaning if you remove the 2 memory sticks you have 0 base memory. The memory slots we're talking about are 200 Pin soDIMM. I am not sure if this type of memory is dual channel or not. I guess thats what I need to find out to answer my question.

I'll research this soDIMM and see what they say about it. If you have anything to add don't be shy

Thanks for your help.

[Jhieminga]

It is not the memory which is dual channel, the motherboard should support this! Normally memory is used on an 'overflow' basis, so with two strips of 1Gb the second strip is used when more than 1 Gb is needed. With dual channel operation, whenever less than 1Gb is needed the motherboard can access both strips simultaneously, basically allowing two memory 'events' at the same time.

[Smurfjet]

Thank you for the explanation.

Something else, my laptop supports up to 4GB memory (2x2GB). Vista 32 bit is said to support this, but I've read reports where it might not take advantage of the totality of the 4 GB. Is this true?

[Mac the Knife]

OS MaxRAM (mobo BIOS limits may be less)

XP(32-bit) - 4GB
XP(64-bit) - ??GB

Vista Starter edition - 1GB (deliberately crippled)
Vista Home Basic, Premium, Business, Enterprise, Ultimate - 4GB
(4GB is an 32-bit limitation that applies to any 32-bit OS, like the 32-bit Linuxes)

Vista x64 Home Basic - 8GB
Vista x64 Home Premium - 16GB
Vista x64 Business, Enterprise, Ultimate - 128GB
(any 64-bit OS, like 64bit Linux or Solaris, can theoretically support 17,179,869,184GB or 16 exabytes of RAM)

[Actually 32-bit OSes can address up to 64GB using Physical Address Extension (PAE) which pages memory in and out rather like the old LIM expanded memory in the dear old DOS 640KB memory days, but we won't go there!]

The cool thing about Vista is that it needs 2GB of memory to do (slowly) what XP does reasonably quickly and the 32-bit Linuxes pretty fast in 512MB....

[Bushfiva]

Smurfjet, your Aspire supports dual channel. As mentioned above, it's chipset feature, not a SoDIMM feature. You'll want DDR2 SoDIMM 533 or 667 depending on the exact model. No harm in just getting the 667.

[Smurfjet]

Bushfiva,

Thanks. I think I will just buy 2 x 2 GB and get it over with. The price will drop after the holidays.

The original plan was to buy 1 x 2GB then buy another one later. But it seems not recommended, and the sticks have to be bought in pairs?

[Bushfiva]

I don't think it will make much difference really, and you should go with what feels comfortable. Even if you put a single 2GB SoDIMM in, you'll have more RAM than most people ever put in their notebooks, and I assume you're not doing 3D gaming. More RAM is always more fun, but the reality is most computers sit around most of the time waiting for the user to press the next key! I'm sure you'll be happy with whatever you decide.

[Mac the Knife]

Honestly, unless you're rendering large images or dealing with huge datasets (which you wouldn't on a laptop anyway) then 2 x matched 1GB sticks will be plenty.

Dual channel mode is faster on the benchmarks and you should enable it if you can - but Vista is such a slow old dog anyway that you won't see any difference in real life.

You won't see any increased performance from 4GB so why spend the money?

[Smurfjet]

At a store here I actually found Kingston 1 x 2GB 30% cheaper than 2 x 1GB.

I figured I'd get more bang for the buck and go Rambo on it