[SOLVED] Will this RAM config work?

xpLoaDeD

Distinguished
May 24, 2013
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Hello everybody, hope you are all fine and good.

I have an old platform with this Motherboard : ASUS M5A78L-M LX with an only 4GB RAM stick at 1333mhz

I want to upgrade to 8gb dual channel config. I can go with 2x4GB 1333MHz or 2x4GB 1600MHz

On ASUS website it says :

"2 x DIMM, Max. 16GB, DDR3 1866(O.C.)/1600(O.C.)/1333/1066 MHz ECC, Non-ECC, Un-buffered Memory
Dual Channel Memory Architecture "

What that " (O.C)" means? I have to oc my cpu? or it means that this mobo only supports 1600MHz ram OCed?

Cpu is a phenom x4 840.


Thanks!
 

Aeacus

Glorious
Ambassador
That OC means about RAM and why it is listed as OC, is because of JEDEC standard, where any RAM speeds faster than JEDEC standard count as RAM OC.

For example:

DDR3 - 1066 Mhz and 1333 Mhz are JEDEC standard, which all DDR3 RAM sticks must be able to run with. Anything faster than these two, like 1600 Mhz, 1866 Mhz, 2133 Mhz etc are considered as RAM OC. But that doesn't mean you can't use e.g 1866 Mhz DDR3 RAM. You can, if your MoBo supports it. Though, you might need to manually enable ("OC") the faster RAM speed from BIOS.

DDR4 - 2133 Mhz is JEDEC standard. And same is with DDR4 RAM as well. All DDR4 RAM sticks must be able to run at 2133 Mhz. However, there are different RAM sticks available, 2400/ 2666/ 3000/ 3200 Mhz etc.

E.g i'm using DDR4 3000 Mhz RAM and while i can run my RAM at 2133 Mhz (JEDEC standard speed), i've enabled XMP profile from BIOS, which lets my RAM to run at 3000 Mhz since it's the max speed my RAM is rated for. In official terms, this counts as RAM OC.

So, even if you go with 1600 Mhz RAM, you can be sure that it will work at 1066 or 1333 Mhz due to the JEDEC standard. So, the RAM works fine in your MoBo. To get the maximum speed of your 1600 Mhz RAM, it may be as easy as selecting different RAM XMP profile from BIOS. If not, your RAM comes with the timings at which it is capable of running at 1600 Mhz. Latter you may need to manually insert in the BIOS, if your RAM doesn't have XMP profile.
 

Aeacus

Glorious
Ambassador
That OC means about RAM and why it is listed as OC, is because of JEDEC standard, where any RAM speeds faster than JEDEC standard count as RAM OC.

For example:

DDR3 - 1066 Mhz and 1333 Mhz are JEDEC standard, which all DDR3 RAM sticks must be able to run with. Anything faster than these two, like 1600 Mhz, 1866 Mhz, 2133 Mhz etc are considered as RAM OC. But that doesn't mean you can't use e.g 1866 Mhz DDR3 RAM. You can, if your MoBo supports it. Though, you might need to manually enable ("OC") the faster RAM speed from BIOS.

DDR4 - 2133 Mhz is JEDEC standard. And same is with DDR4 RAM as well. All DDR4 RAM sticks must be able to run at 2133 Mhz. However, there are different RAM sticks available, 2400/ 2666/ 3000/ 3200 Mhz etc.

E.g i'm using DDR4 3000 Mhz RAM and while i can run my RAM at 2133 Mhz (JEDEC standard speed), i've enabled XMP profile from BIOS, which lets my RAM to run at 3000 Mhz since it's the max speed my RAM is rated for. In official terms, this counts as RAM OC.

So, even if you go with 1600 Mhz RAM, you can be sure that it will work at 1066 or 1333 Mhz due to the JEDEC standard. So, the RAM works fine in your MoBo. To get the maximum speed of your 1600 Mhz RAM, it may be as easy as selecting different RAM XMP profile from BIOS. If not, your RAM comes with the timings at which it is capable of running at 1600 Mhz. Latter you may need to manually insert in the BIOS, if your RAM doesn't have XMP profile.
 

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