Does number of ram dims matter?

Hello,

I was wondering if someone could help me with a question on if the number of dimms matter. I am currently in the process upgrading the ram in our lab's workstation that we need use for bioinformatics to 32gb. To future proof things a bit I thought about getting 2 x 16gb vs 4 x 8gb dimms as we will be able to add more ram later down if we need more ram. So my question is does going with 2 dimms vs 4 dimms cause any decrease in performance?

The workstation is a Dell Precision Tower with two cpu sockets so each cpu only has 4 dimm slots. Currently we only have one of the sockets populated with a Xeon 2630 V3. The analysis that we are currently running 12 hours to complete so we will need all the performance we can utilize.

Thanks

Shouldn't really make a sizeable difference. ECC would probably be recommended with such long running times, assuming the board supports it (99% sure it does)

Yes the board supports ECC ram. It currently has 16 gb ram installed but its 4 x 4gb so i cant any more, so this is the dilemma I want to avoid.

Speed diff should only be around 1-2% unless you're using an APU and is Gaming with it. RAM speed really doesn't mater that much, since RAM bandwidth quite well live up to what your CPU uses.
depending on if your MOBO supports quad channel, maybe that would make a small dent, but imo dont expect a 30% increase.
Basically single, duo, and quad channel memory is all about the bandwidth, and unless you're an GPU, then bandwidth really doesn't mean that much, hense we have GDDR, and DDR memory.

with 2 sticks of ram you can get as high as 25gb/s bandwidth and with 4 sticks you get 50gb/s. weather it makes a difference or not depends on what you use it for. if all your doing is spreadsheet work you likely won't notice anything. but for rendering you might see a reasonable boost provided your cpu and gpu aren't already choking.

If your software will take advantage I would occupy that spare CPU slot asap.

While I agree with this, in my case I went with 4 dimms because:
1. I don't need more than 4x4=16GB and
2. I figured that 4 dimms will run cooler than 2 dimms. Not that it matters.

you could probably leave two sticks at 4 so 8 4 8 4 in the slots giving you 24gig total, would give it a try on one of you machines and see if there is any gains vs running 8 0 8 0.

There are edge cases where there is a difference in speed due to the number of dimms but those are vastly smaller than for ex. just upping the speed of the ram which in itself isn't that much.

Also as said before, if the processing run is CPU-bound and capable of using more cores, add the second cpu.
If the program is memory-bound, add more memories, preferably happy ones as to not depress your computer and since we are talking about a server motherboard, check the specs on what kind of memory to add because they tend to be kind of picky on what memories the like in which slot.

Most likely you will see little to no difference between the amount of dimms