I am currently building a new server. I have options between say

32GB Memory for 2 CPUs, DDR3, 1066MHz (8x4GB Dual Ranked RDIMMs)


36GB Memory for 2 CPUs, DDR3, 1066MHz (18x2GB Dual Ranked RDIMMs)

Both at the same price.

Should I go for the higher ram amount or the fewer chips?

This will be for a Dell PowerEdge R710 with two Intel® Xeon® E5530, 2.4Ghz, 8MB Cache, 5.86 GT/s QPI, Turbo, HT


  • It would be very helpful to know what processors you're planning on using in this system, ideally the server's make and model too please
    – Chopper3
    May 20, 2009 at 6:53
  • Good point Chopper, have edited. May 20, 2009 at 7:06

5 Answers 5


Thanks for the update Alex. Most new 'Nehalem'-based servers such as the model you're looking at use triple-channel RAM, notice how they have 'divisible-by-three' memory slots (3, 6, 9, 12, 18 etc) where previous models had 'devisible-by-two' versions (2, 4, 8, 16 etc). You can put less than three modules in at a time but you're likely to miss out on the full performance of the new 'QPI'-based memory architecture.

Also of great importance with these new chips is to balance your memory across processors - if you only have a single processor then you shouldn't put memory in the slots associated with the empty processor slot, only with the first processor - this effectively halves the memory capability of single-processor servers. If you have two processors you need to ENSURE that they both have the same amount AND type/size of memory as each other.

Now onto your actual question. With these new servers the more physical memory chips you use the slower they get - they're still faster than the previous generation of chips/memory even at their slowest but you should aim to use less of the most capacious modules that make sense to you financially.

Looking at the specific machine you want I would urge you to go with either 48GB Memory (12x4GB) or 24GB Memory (6x4GB) based on your requirements. Best of luck.


I would go for fewer chips, the reasoning being:

  1. This may leave some slots available for more RAM at a later date if necessary.
  2. When you decommission the server 3+ years from now, the 4 GB chips are more likely to be useful for salvaging than the 2 GB ones.

I doubt having lots of chips would give you any noticeable performance improvements in most scenarios.


Higher density has nothing but benefits

  • Upgrade easily
  • More reliable
  • less power used (those few Watts tend to accumulate...)

The impact of triple vs. dual channel will not be so outspoken. However, within a triplet, your memory should be matched, so starting with 8 dimms now and expanding later might be more challenging unless you would be prepared to lose 2 dimms at that time. Do you need the memory right now? Then take the 18x2GB. Is it a luxury for now, and you are comfortable with upgrading later, go with 9x4GB if you can.


The short, easy answer to this is neither. Yet, with fewer chips, your data pulse takes less time to run-through the ram stick than if you had twice as many of those little buggars. This is, of course, a bit of a hairbrained answer, but in casual surfing and personal computing, the speed at which your signals run-through your ram is always best when it is faster (less chips, typically but NOT NECESSARILY). This is a great one for you Devil's Advocates out there! You can look at the chips as "resistors" of sorts, if ya' really need it to be a simple "picture" in your mind.

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