6gig triple channel vs 8gig dual channel

ski

Member
Jan 15, 2000
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I had someone bring over their computer some small shop built for him because it was shutting down. Turns out it was the Tiger power supply fan stopped working. But when I opened it up I noticed they had installed 8 gig of OEM Crucial CT25664BA1339 ram (4-2gigs) in a triple MSI X58M motherboard. His daughters use the computer and I don't think they need 8 gigs but wondered if 6 gigs in tri-channel would be better then the 8 gigs now working in dual-channel? Thanks for any help.
 

Gunbuster

Diamond Member
Oct 9, 1999
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I think the way to look at it is the computer will be a few % faster in Triple channel mode but then an order of magnitude slower if it ever uses more than 6GB. I would leave it alone.
 

Morg.

Senior member
Mar 18, 2011
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Are you sure they're working in dual channel ?
IIRC modern motherboards could have triple channel with single channel and that type of weird configurations (or maybe I misread at some point).

Either way his daughters won't see the difference between both (as mostly noone could see it anyway except benchmarks), be it triple + single or effective dual across the 4 sticks.

"Normal" people will prefer 8 Gigs if they can use them, although they won't, because they're normal.
On the other hand they will not use the increased bandwidth either ... so just take one stick off, sell it on ebay and that's it :)
 

jjmIII

Diamond Member
Mar 13, 2001
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Are you sure they're working in dual channel ?
IIRC modern motherboards could have triple channel with single channel and that type of weird configurations

I think you might be right....

I'm sure the answer is here somewhere.

Use cpu-z to check.
 

InfoTiger

Golden Member
Sep 10, 2004
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Hm just the question I'm having for a quit while.
I have 4x2g in my system. The CPU-Z says they are triple.
Wonder how they work?
 

ski

Member
Jan 15, 2000
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Thanks for feedback. Not sure about the dual channel because I can't fire up the computer yet till new power supply comes today but whoever built it had the 4 sticks in A0,B0,C1, and C0 which according to the book is wrong for 4 sticks. Manual A1,A0, B0, and C0 for 4 sticks. I'll try cpu-z when I fire it up.
 

PUN

Golden Member
Dec 5, 1999
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Thanks for feedback. Not sure about the dual channel because I can't fire up the computer yet till new power supply comes today but whoever built it had the 4 sticks in A0,B0,C1, and C0 which according to the book is wrong for 4 sticks. Manual A1,A0, B0, and C0 for 4 sticks. I'll try cpu-z when I fire it up.

Read the manual or google at least.
4x 2gig runs triple channel with one gig being single. U r always better off going 8 vs 6
 

Denithor

Diamond Member
Apr 11, 2004
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Are you sure they're working in dual channel ?
IIRC modern motherboards could have triple channel with single channel and that type of weird configurations (or maybe I misread at some point).

http://www.anandtech.com/show/2658/5

In the four-slot configuration the first three slots correspond to the first three channels, the fourth slot is simply sharing one of the memory channels. The downside to this approach is that your memory bandwidth drops to single-channel performance as you start filling up your memory. For example, if you have 4 x 1GB sticks, the first 3GB of memory will be interleaved between the three memory channels and you'll get 25.6GB/s of bandwidth to data stored in the first 3GB. The final 1GB however won't be interleaved and you'll only get 8.5GB/s of bandwidth to it. Despite the unbalanced nature of memory bandwidth in this case, your aggregate bandwidth is still greater in this configuration than a dual-channel setup.

And if you look at the benchmarks, the dual versus triple channel bandwidth makes almost no difference at all.

Short answer: leave all four sticks in there, if they ever happen to use more than 6GB they will be happy to have an extra 2GB @ single channel bandwidth.
 

ski

Member
Jan 15, 2000
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Thanks guys for clearing this up for me. I'll leave all 4 sticks in then.
 

nanaki333

Diamond Member
Sep 14, 2002
3,772
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Are you sure they're working in dual channel ?
IIRC modern motherboards could have triple channel with single channel and that type of weird configurations (or maybe I misread at some point).

Either way his daughters won't see the difference between both (as mostly noone could see it anyway except benchmarks), be it triple + single or effective dual across the 4 sticks.

"Normal" people will prefer 8 Gigs if they can use them, although they won't, because they're normal.
On the other hand they will not use the increased bandwidth either ... so just take one stick off, sell it on ebay and that's it :)

yep. my wife's intel s1366 mobo has 4 DIMMs.
 

Emulex

Diamond Member
Jan 28, 2001
9,759
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3 channels are 3-way interleaved
the 4th channel is 1-way interleaved. that 4th chip will run at 33% as the other 3 chips.

but swapping is slower than both scenario's above. so pick your poisin