Question PC Not Supporting DUAL CHANNEL RAM even when my MOTHERBOARD SUPPORTS DUAL CHANNEL RAM and Has 2 RAM SLOTS

Vijendra_Gaur

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Oct 15, 2015
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I have BIOSTAR A55 ML2 Motherboard which supports DUAL CHANNEL RAM and also has 2 Ram slots, A1 and B1, Now the problem is that i purchased it with 4 GB DDR3 1333 Ram, Few weeks ago I retrieved a Spare Ram of 2 GB DDR3 1333 Ram, Now when plugged both ram to my motherboard, In PC Property It's Showing 6GB of total ram, But only 4 GB Usable, Even software CPUZ is showing single channel 6 GB Ram. It's Written on my Motherboard clearly DUAL CHANNEL DDR3 A1 B1, Please Help as I do not have such knowledge about RAM All I knew was that it should be same frequency to run 2 Ram together and motherboard should support dual channel which both are positive in my case then why am i not able to use both ram at same time and only 4 GB is usable even when it shows 6 GB in total.
 
What CPU do you have currently installed?
Do you use the integrated graphics?
If you're using integrated graphics, then those missing 2GB of RAM are reserved for the iGPU.

Also you're not running in dual channel fully unfortunately... that's why it's maybe showing single channel.
Having 2 modules with different capacities you'll be running in flex mode... the 2 GB module + 2GB from the 4 GB module will run in dual channel, while the remaining 2GB runs in single channel.
To run in dual channel completely you'll need sticks with identical capacities... 2x2, 2x4,2x8, etc.
 

bignastyid

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I don't think that old FM1 cpu supports flex mode. So with that mixed ram it will all be single channel.

Does task manager show 4gb available and 2gb in hardware reserve? Are you using an apu graphics or a dedicated gpu?
 
I don't think that old FM1 cpu supports flex mode. So with that mixed ram it will all be single channel.

Does task manager show 4gb available and 2gb in hardware reserve? Are you using an apu graphics or a dedicated gpu?
He has an FM2 socket board though. It may be possible for these to support asymmetric dual channel(flex) as FM2+ CPUs did.
 
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Vijendra_Gaur

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Oct 15, 2015
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I don't think that old FM1 cpu supports flex mode. So with that mixed ram it will all be single channel.

Does task manager show 4gb available and 2gb in hardware reserve? Are you using an apu graphics or a dedicated gpu?
I am using Integrated GPU of AMD A4-4000 APU, Task manager shows 1.8/3.2 in RAM Section
 

Vijendra_Gaur

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He has an FM2 socket board though. It may be possible for these to support asymmetric dual channel(flex) as FM2+ CPUs did.
Then Why would they write DUAL CHANNEL DDR3, I also checked their website it's also mentioned that these motherboard support dual channel ram.
 

bignastyid

Titan
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Then Why would they write DUAL CHANNEL DDR3, I also checked their website it's also mentioned that these motherboard support dual channel ram.
Full dual channel ram requires both sticks to be the same size and compatible. Its reccomended to buy them in a matched set for best compatibility.

You are running a mixed set. You should feel lucky they are working together at all.
 

Vijendra_Gaur

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Oct 15, 2015
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What CPU do you have currently installed?
Do you use the integrated graphics?
If you're using integrated graphics, then those missing 2GB of RAM are reserved for the iGPU.

Also you're not running in dual channel fully unfortunately... that's why it's maybe showing single channel.
Having 2 modules with different capacities you'll be running in flex mode... the 2 GB module + 2GB from the 4 GB module will run in dual channel, while the remaining 2GB runs in single channel.
To run in dual channel completely you'll need sticks with identical capacities... 2x2, 2x4,2x8, etc.
I know that 2 GB is reserved for my integrated GPU, But i have an option to set how much memory i want to use for GPU in bios settings for this, Currently I have opted for AUTO as shortage of RAM, But when i Save it for 2 GB, Still only 1.96GB shows usable Out of Total 6 GB RAM in Pc Property and in tast manager again shows only 4 GB total available memory, In CPUZ again it only shows single channel 6GB.
I'm Sure that my RAM are not running together and only 4GB single stick is being used.
 

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