Two 2 GB memory sticks coexisting with two 1 Gb memory sticks?

rmmarsh
rmmarsh used Ask the Experts™
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I currently have 2 Gb on my MB... I have 4 slots, two (2) of which have 1 Gb memory sticks in them.  (PC5400 DDR2 667 Mz).

Can I add two sticks of 2 Gb memory to the other two slots (thus having 1 Gb in two slots, and the 2 Gb sticks in the other 2 slots), or do I have to replace the 1 Gb sticks and go with 2 Gb sticks in all four slots?  (Money is the issue here, I would like to hang on to the 1 Gb memory sticks until I get more funds).
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Gary CaseRetired
Most Valuable Expert 2013
Top Expert 2009
Commented:
Sure.   That'll work fine.
Gerwin Jansen, EE MVETopic Advisor
Most Valuable Expert 2016

Commented:
This depends on the motherboard in your computer. You should have a look in your mb manual, answer should be there. Do you know what mb you have?
Gary CaseRetired
Most Valuable Expert 2013
Top Expert 2009

Commented:
... two caveats:
     (1)  Be sure you use the correct type of memory (DDR2) and with a speed rating at least as fast as your current modules (otherwise you'll slow down your memory speed)
     (2)  Assuming your current two modules are installed correctly for dual channel operation, you simply need to install the new modules in the other two slots.     If you're not sure, run MemTest FIRST before you install the new modules and confirm your memory is running in dual channel mode -- and if not, move one of your current modules to the other channel so you get dual channel operation.    Then simply install the other two modules in the remaining two slots.
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As mentioned it depends on the motherboard. What os and is it 32-bit or 64-bit? If its 32-bit it wont take advantage of anything over 4gb anyway(usually a 32-bit os will 3.5Gb or less as usable).
Gary CaseRetired
Most Valuable Expert 2013
Top Expert 2009

Commented:
I've yet to see a motherboard that supports 2GB modules that won't work fine with a pair of 2GB and a pair of 1GB modules installed ... so I wouldn't say it depends on the motherboard (unless it's so old that it won't support 2GB modules).      It is, of course, true that whether the memory will be USED or not depends on whether the system is running a 64-bit OS.

Dave BaldwinFixer of Problems
Most Valuable Expert 2014

Commented:
Some motherboards do require the pairs to be matched at least for specs if not brand.

Author

Commented:
garycase:  I downloaded Memtest 4.20, ran it and saw nothing about "dual channel mode".  What should I be looking for?  Also, when I look at the slots, they are 240 pin - one of the slots is white, the other is black, for both banks of 2 each.  Is this normal?
Gary CaseRetired
Most Valuable Expert 2013
Top Expert 2009

Commented:
Yes, that's normal.   In most cases, the colors match the slot # within a channel -- so, for example, your current two modules should both be in white slots (or both in black slots).     If your motherboard supports dual channel operation (which is almost certainly does since the slots are color-coded), MemTest should note that it's operating in dual channel mode if the memory is installed correctly.

Note the screenshot here:  http://www.memtest.org/pics/i875-big.gif
... you'll see "Dual Channel" on the 7th line.    If you're not seeing that, your system is most likely not operating in dual channel mode.    If you have both modules plugged into the same channel, that would explain why.

Author

Commented:
HI Gary... both modules are in the white slots, but no dual channel... is there a BIOS setting?
Gary CaseRetired
Most Valuable Expert 2013
Top Expert 2009

Commented:
There may be a BIOS setting -- won't hurt to check.

It's also possible that your motherboard uses the color codes differently (some do) -- and that you need the first two modules installed in the first white and first black slot.    If there's no BIOS setting, then just move one module and see if that then gives you dual channel mode.

Finally, it's also possibly that you're running a system that doesn't support dual channel operation -- in that case it makes no difference which slots you install the memory in ... although if that's the case I'd put both 1GB slots in white slots, and both 2 GB modules in black slots just for consistency.

If you post the make/model of your motherboard I can be more precise -- but if you simply try moving one module and double-check the BIOS for a single/dual channel setting you'll have done everything you can anyway.
Gerwin Jansen, EE MVETopic Advisor
Most Valuable Expert 2016

Commented:
>Do you know what mb you have?

There's lots to tell in general about motherboards, memory, dual channel etc. Can you post you MB brand / type?

Author

Commented:
Motherboard: Nvida
BIOS: Phoenix
Chipset: nVida nForce 680i SLI SPP
Retired
Most Valuable Expert 2013
Top Expert 2009
Commented:
Your board does not support dual channel memory ... so you can populate the slots any way you want.   It does support 2GB modules ... so there's no problem mixing and matching with your existing 1GB modules.

Author

Commented:
Thank you so much for your time... I appreciate it!

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