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I bought this ASUS Sabertooth X58 motherboard from

But I'm not sure what DDR3 RAM to buy.

I haven't built a PC from scratch in about 3 years, and I'm wondering the following:

  • Do DDR3 ram chips need to be installed in three at a time? Or can I just install one or two now and install more later without any particular pattern?
  • If I buy 2000MHz RAM from Corsair, will that work at 1866 MHz? (which is the highest frequency the motherboard supports)
  • Is it just me or is 1866 RAM not around?
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up vote 2 down vote accepted

You can install DDR3 sticks in any way you want. If you do chose to install them in groups of two or three, you can use dual or triple channel for access. You can also add sticks later if they are sufficiently similar.

RAM can generally be downclocked, so it should work fine at 1866 MHz. Also note that there may be some restrictions on frequency, so do read motherboard manual.

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Thanks, what's "double/triple channel access" mean? Also, what am I looking for in the motherboard manual about memory frequencies? – CVertex Mar 20 '11 at 20:07
@CVertex Sorry, I used wrong term. See new edit. – AndrejaKo Mar 20 '11 at 20:08
@CVertex There should be somewhere a list of supported modules. Look for any footnotes or similar. If I remember correctly, some motherboards for X58 wouldn't work at full frequency when RAM is in tripple-channel mode, so it could happen that RAM you buy will be to fast for motherboard and you'll waste money that way. – AndrejaKo Mar 20 '11 at 20:12
@CVertex When I mentioned searching the manual, I was thinking at something like this quote form the site:*Hyper DIMM support is subject to the physical characteristics of individual CPUs. Some hyper DIMMs only support one DIMM per channel. Refer to Memory QVL (Qualified Vendors Lists) for details. I'll try to find some info on the web site of Asus. – AndrejaKo Mar 20 '11 at 20:24
Thanks mate! I got the 2GHz and read the manual.. I'm gonna wait for my parts to arrive and see if your answer is right.. I'm sure it is :) – CVertex Mar 24 '11 at 3:00

As well as the other answer, try to avoid memory that isn't on the Qualified Vendors List, or buy from somewhere with a compatibility guarantee, like crucial. When I bought mine, I bought the cheapest memory I could find, and it did not work at all, I ended up buying from Crucial instead.

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