I have a fairly old motherboard - a Pegatron Narra6 M2N68-LA - and when I google for it, I get this page on hp.com: https://support.hp.com/us-en/document/c01925534

I currently have 2 x 2 GB DDR 1333 sticks. I've bought two sticks of 4 GB DDR3 1600 RAM, but now I'm stating to wonder, whether the frequency mismatch may be a problem.

Now, I'm not thinking of mixing the two, since the motherboard only has two RAM slots. I'm thinkng of replacing the 2x2 GB with 2x4 GB.

The reason for my concern is that the hp.com link says:

Supported DIMM types:

  • PC3-8500 (DDR3-1066)

  • PC3-10600 (DDR3-1333)

I friend told me the 1600 MHz RAM might use too much power for the motherboard - is that a valid concern?

My CPU is 64-bit (AMD Athlon X2) and my OS is 64-bit Ubuntu. I don't suppose the motherboard is limited to only 4 GB RAM?


First could you make sure that your old DIMS are DDR3 or are they DDR2 ? Just checking, because even the board supports DDR3 your processor may not. Could you tell the specific model of your processor too please ?

Incase the old DIMS are DDR3 -> your cpu supports DDR3 then ->

I suggest that you plug only one of the new DDR3 dims in to the board and chech if the system boots up, if the systems boots, try adding the another dim too, if you cant boot after abother dim there can be 4GB memory limit by the board. If the system does not work even with only 1 dimm there could also be 2GB memory limitation for one memory line.

Your system does not really care if the dim is1600mz if your board / cpu cant run the memory at 1600mz the memory will be underclocked automaticaly by your bios.

Your new dims can run just fine at 1333 for example ( you can always run your memory underclocked no problem )

If you have the knowhow you can make sure that the memory is actualy running at 1333mz if you are able to boot your system with 1 or 2x new dims by entering the Bios ( if your board supports that ) and manually setting the memory speed to 1333mz ( not sure if your board supports this thou. )

There can be memory limitation of 4GB, but cant be sure about that.

The following information from the link you suplied. ( 4GB "limit" for 32-bit, does not mean that the board it self does not support more if running 64-bit os )

Dual channel memory architecture Two DDR3 DIMM (240-pin) sockets Supported DIMM types: PC3-8500 (DDR3-1066) PC3-10600 (DDR3-1333) Non-ECC memory only, unbuffered Supports 2GB DDR2 DIMMs Supports up to 4 GB* on 32 bit PCs *32-bit operating systems cannot address a full 4.0 GB of memory


(TLDR) Check if your old dims actualy are DDR3

If so try using only one new dimm ( only one ram stick installed ) and check if the system boots up.

If system boots up with one dimm add another and check if system boots up againg.

If system does not boot with 1 dimm there can be memory limitation per memory line of 2 GB

If the system does not boot with 2 dimms there can be memory limitation ( for bouth lines ) of 4 GB

You board / cpu / new DDR3 does not care if the dimms are 1666Mhz the memory speed will be undercloked to running at 1333Mhz ( DDR3 default ) and your new ram does not care about that and should work just fine at 1333 Mhz.

( i have mix ddr3 setup by my self ) 1600Mhz Ripjaws 2x 8GB Default voltage ( 1.5V )

2300Mhz ( cant remember brand ) 2 x 4GB Default voltagr ( 1.8 V )

I am running them at 1750Mhz and voltage 1.59 V And in between timeings and they work together just fine.

Sorry for messy text. I was tired and not good at writing text, but wanted to help. Let me know if you got any results.

Best regards, Visdmin Finland


A DDR memory module can always be run at a slower speed than they are labelled for, and the voltage for DDR3 is standardized at 1.5V. Only low-power or overlocked RAM would differ from that voltage, so just make sure the sticks say 1.5V on the label and there should be no electrical problems to worry about.

The CPU and motherboard are ultimately responsible for setting the speed of the RAM, so if the system is not capable of running at 1600Mhz it would automatically set those modules to run at the fastest speed that it can support.

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