APU Uneven Dual Channel?

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SM125

SM125

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I have an AMD A10-6800k APU and recently noticed the performance slacking and windows experience index scores a lot lower than others with this APU, a few searches later it turns out to be the fact that I'm running 1x 8gb 1333hz stick of ram in single channel so I'm restricting the gaming side of things quite a lot (my WEI gaming score is 4.4 as opposed to everyone else's 6.2)

If I bought a 2gb 1333 stick of the same brand ram, would it let me run in dual channel with an 8gb and 2gb?
And also would I still receive a large benefit like others were by perfectly matching their ram up? Thanks!
 
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You can mix different brands, speeds, etc. of RAM between channels but all installed RAM will run at the slowest speed and timings of the bunch.

If you have uneven configuration between channels, you end up in interleaved mode where the address space is split between channels so each memory request only has half as much bandwidth available.

If you have identical configuration on both channels, memory requests get serviced using both channels symmetrically and this produces twice the bandwidth.
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Titan
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May 18, 2007
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For dual channel to work properly, both channels must have perfectly matched configuration - same-sized DIMMs with the exact same electrical configuration in the equivalent position of each channel.

Anything else will cause the memory controller to either fall back to normal interleaved or fail to work altogether.
 
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SM125

SM125

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I've seen people running different speeds, sizes and brands together in dual channel though, how did they manage that? My thought was that even if I got just a 2gb stick of the same ram to get me into dual channel it'd still have a significant impact on performance as APUs are so sensitive to dual channel and high speed ram.
 
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Titan
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May 18, 2007
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You can mix different brands, speeds, etc. of RAM between channels but all installed RAM will run at the slowest speed and timings of the bunch.

If you have uneven configuration between channels, you end up in interleaved mode where the address space is split between channels so each memory request only has half as much bandwidth available.

If you have identical configuration on both channels, memory requests get serviced using both channels symmetrically and this produces twice the bandwidth.
 
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Solution
SM125

SM125

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Trying my best to understand this as I'm pretty new to it all, I'm sure you can tell.

So, would I see any performance increase on my APU whatsoever going from Single channel to Interleaved? I apologise if I'm just asking stupid questions!
 
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Titan
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Only if AMD's memory controller is capable of handling request to both channels concurrently. I have no idea if it actually does but considering how asymmetrical configurations are not recommended and supporting it beyond the basic capability would require extra work, I doubt AMD bothered to optimize that.
 
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