Using 3 ram sticks on a dual channel motherboard

R4GE199

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May 2, 2014
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I have Asus Maximus VI Gene motherboard and have currently installed Corsair Vengeance 2x4GB 1600mhz CL9 in dual channel mode. I want to upgrade my ram to 16GB and one of my ram slots is blocked by my CPU cooler so I am planning to buy vengeance 8GB and install it in the remaining slot. I want to know if I can run the system in such configuration and what are its pros and cons. Also if it runs, will it be stable?

Thank you.
 
Solution
Big question is the one you already asked 'IF it will work', there are no guarantees when mixing DRAM, see my article (item 2) here:

http://www.tomshardware.com/reviews/ddr-dram-myths,4155.html

and to clear up the rest mentioned above, if you try and they will play, put the 8GB stick in slot 2 from CPU and the 4GB sticks in slots 3-4 - this way you have 8GB in each channel and it will operate in full dual channel mode, otherwise if you have the 4GB sticks in 2-4 and stick the 8GB in slot 3 you have 4GB in channel A and 12 GB in channel B - under flex mode (see this one (item 7)

http://www.tomshardware.co.uk/ddr3-dram-faq,review-33220.html

you will have 8GB running in Dual and the odd 8 in single channel mode.
you will get 16gb of ram available (and probably stable) but not in dual channel. it's impossible with an odd number of sticks. even 4x4 doesn't work sometime or is unstable (in dual channel, single channel 4x4 works ok most of the time). your best bet is to get a 2x8 kit and sell the old kit.

edit: dual channel will not work, but the ram should function ok without instability.
 

Rookie_MIB

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Agreed ^^ It should work, but it will default into single channel mode and put all the RAM in one pool. Best idea is to sell the 2x4GB and get a 2x8GB kit, the best reason being optimum performance and guaranteed compatibility. Mixing sticks from different batches can sometimes create issues.
 

R4GE199

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May 2, 2014
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I read somewhere that the 2x4GB will work in dual channel while the 8GB one will work in single channel. I read my motherboard's manual and its also stated there. But i want to know from someone who has tried it.
 

Tradesman1

Legenda in Aeternum
Big question is the one you already asked 'IF it will work', there are no guarantees when mixing DRAM, see my article (item 2) here:

http://www.tomshardware.com/reviews/ddr-dram-myths,4155.html

and to clear up the rest mentioned above, if you try and they will play, put the 8GB stick in slot 2 from CPU and the 4GB sticks in slots 3-4 - this way you have 8GB in each channel and it will operate in full dual channel mode, otherwise if you have the 4GB sticks in 2-4 and stick the 8GB in slot 3 you have 4GB in channel A and 12 GB in channel B - under flex mode (see this one (item 7)

http://www.tomshardware.co.uk/ddr3-dram-faq,review-33220.html

you will have 8GB running in Dual and the odd 8 in single channel mode.
 
Solution

Rookie_MIB

Distinguished


Ah yes, I guess I didn't think about that although I do remember reading about that a while back. If both channels have equal pools of RAM, it will run in dual-channel mode. It doesn't matter about the sticks, it matters on the pool size.