# Odd number of memory sticks.



## cly (Nov 12, 2010)

This may be a dumb question but how do you run an odd number of memory sticks?  I see that a lot of PCs come with 6GB ram.  I assume is it 3x2gb.  I thought ram sticks are supposed to be paired up. Do you need a special board?  thanks


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## Black Panther (Nov 12, 2010)

I'm not sure I understand your question.
However by 'paired up' you intend running in dual channel or triple channel in which case you have identical sticks of the same size in two or three slots (depending if the motherboard supports dual channel or triple channel)

However in these cases you can still put unpaired / odd sticks - at the expense of slight loss in performance. Personally in my desktop I've occasionally put ram 2GB, 2GB and 1GB (my mobo's got 4 slots and supports dual channel) and I didn't see any visible difference.


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## animal007uk (Nov 12, 2010)

Some of the new intel I series of cpu's suport tripple channel memory (3x2gig) But if you have a pc like mine that only does dual channel then you could have 2x2gig sticks and 2x1gig sticks to make up 6gig but this would still be dual channel mode.

you could also have 1x2gig and 1x1gig sticks but you would most likely lose dual channel mode.

hope that makes sense 

Another way to put it would be like this, Lets say you have 2x2gig of ram, Your pc will probably be running in dual channel mode, Now lets say you add another stick of ram that is 2gig in size, You will now have 6 gig but probably have lost dual channel mode as the 2gig is a single stick.

I don't think there is such thing as odd memory sizes, If you go back a good few years, Most pc's came with 1 stick of ram as dual channel was a new thing back then. I don't think much has changed over the years in the sense that you can use any size of suported ram on your mobo, It's just you lose dual channel mode or tripple channel mode.


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## Athlon2K15 (Nov 12, 2010)

cly said:


> This may be a dumb question but how do you run an odd number of memory sticks?  I see that a lot of PCs come with 6GB ram.  I assume is it 3x2gb.  I thought ram sticks are supposed to be paired up. Do you need a special board?  thanks



Yes you need a special board to run 3 sticks, Its called X58. Its for triple channel (192bit) ddr3 on intels 1366 platform.


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## animal007uk (Nov 12, 2010)

AthlonX2 said:


> Yes you need a special board to run 3 sticks, Its called X58. Its for triple channel (192bit) ddr3 on intels 1366 platform.



You are right in that sense but most pc's can still run 6gig so no you dont need special hardware, It just means you have no dual channel mode when using older style chipsets/memory controler if i remeber right.

I have an intel P45 chipset DDR2 (i have 4 ram slots) 2 are used up with my 4gig of ram but i can add another 2 gig (single stick) but then i have no dual channel mode.


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## cadaveca (Nov 12, 2010)

INtel has this neat thing called "flexmem" that allows to retain dual channel with three sticks in 775 and 1156, and triple channel with 4 sticks on 1366, with no performance drop. the extra stick is put on it's own channel, and the remaining dual/triple channel config stays as if the odd stick doesn't exist.

Amd also has similar tech.


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## animal007uk (Nov 12, 2010)

cadaveca said:


> INtel has this neat thing called "flexmem" that allows to retain dual channel with three sticks in 775 and 1156, and triple channel with 4 sticks on 1366, with no performance drop. the extra stick is put on it's own channel, and the remaining dual/triple channel config stays as if the odd stick doesn't exist.
> 
> Amd also has similar tech.



Thank you been a while since i checked into it all.

Is it a bios thing though? or will windows work it out without any bios tweaks?
I would test but i don't have a spare 2 gig stick and this pc has been a pain since day 1 with ram lol. But thats another story.


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## cadaveca (Nov 12, 2010)

100% automatic, at least, unless OEMs nerf the bios, but I haven't run into any issues with this particular feature. We recently had a poster asking the same question, I asked him to run benches with the extra stick, results were exactly the same. He didn't have to do anything other than pop the stick in. Memory controller should be configured before you even get to POST screen, so this is invisible stuff to the OS.


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## newtekie1 (Nov 12, 2010)

6GB could also be 2x2GB and 2x1GB, so 4 sticks.  That would still give dual-channel.

I've also seen 3GB in a 2x1GB and 2x512MB configuration.  HP loved to do this.


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## robn (Nov 12, 2010)

cadaveca said:


> INtel has this neat thing called "flexmem" that allows to retain dual channel with three sticks in 775 and 1156, and triple channel with 4 sticks on 1366, with no performance drop. the extra stick is put on it's own channel, and the remaining dual/triple channel config stays as if the odd stick doesn't exist.
> 
> Amd also has similar tech.



Nice, thanks I didn't know that.

So to summarize:
Any combination of RAM sticks sizes can be run, but in certain combos there can be performance benefits, e.g. paired sticks on a dual-channel board or triplet sticks on a tri-channel board (only X58 for now?). And now it looks like the performance benefits can be cleverly retained on modern mixed setups too.


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## cadaveca (Nov 12, 2010)

Pretty much. This is not new stuff(Flexmem has been around for YEARS now), but the lack of performance impact on running a mis-matched config is relatively new, with 1156 and 1366.


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## scaminatrix (Nov 13, 2010)

cly said:


> This may be a dumb question but how do you run an odd number of memory sticks?  I see that a lot of PCs come with 6GB ram.  I assume is it 3x2gb.  I thought ram sticks are supposed to be paired up. Do you need a special board?  thanks



What AthlonX2 said. You're using "Dual Channel DDR2" (that gets paired up as you said). There's now something called "Triple Channel DDR3" and you have 6 memory slots on the motherboard, as opposed to the 4 on your board.


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## hat (Nov 13, 2010)

3x2gb is common on the x58 platform. Tri-channel.

On non-x58, you could get dual-channel 6GB with 2x2gb and 2x1gb.

3x2gb is possible without x58, but it will be single channel.


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