64GB RAM: 2x32GB or 4x16GB for a Ryzen 9 5900X?

I recently built a new system for myself, and I will be going to 64 GB of RAM for some work tasks. I am curious if I should just get another 32GB (2x16GB) kit or return my current 32GB (2x16GB) kit and just get a 64GB kit (2x32GB)?

The G.Skill kit I am using is at 3600 MHz at 14-14-14-34 and 1.45 volts. If I move to a 2x32GB kit at 3600 or higher, I know it will have a higher CAS. Is there any benefit to going higher than 3600 MHz on the X570s platform with Zen 3?

Workstation specs:

  • AMD Ryzen 9 5900X
  • Gigabyte X570S Aorus Elite AX
  • G.Skill Ripjaw F4-3600C14D-32GVKA
  • Samsung 980 Pro 1TB
  • AMD Radeon 6700XT

youd need to look at data to be sure but id say the benefits would be in the margin of error territory

I wouldnt bother

1 Like

Yeah, that is what I thought. I will stay at 3600 Mhz.

i run 2x32, not a fan of 4 dimms

1 Like

I will go the 2x32 route and just return the 2x16Gb kit.


128gb now? or do you mean 2x32

That was a typo. Still doing 64GB.

Looks like some nice B-die. Assuming these are single-rank DIMMs, and assuming you can find the exact same kit, that would be fine and possibly even preferable. According to longtime overclocker The Stilt, Ryzen processors with two CCDs seem to prefer four single-rank DIMMs over two dual-rank DIMMs.

On the other hand, it’s a pretty pricey kit and it will probably be more expensive to buy another one than a more garden-variety 2x32GB kit of e.g. DDR4-3600 CL16. And if the second kit you buy isn’t a close-enough match, it might be hard to run all four DIMMs at these timings. Ultimately it’s going to boil down to the quality of your processor’s IMC.

1 Like

2* 16GB B die kits are dual rank.

I’d say return the kit and get 2* 32GB kits. Running 4 sticks of dual rank B die DIMMs is pretty damn difficult unless you’re willing to settle for lower frequency and looser timings (at which point you might as well get the cheaper stuff because you’re not fully leveraging B die’s strengths; tight primaries and tRFC).


Good advice, thanks.

With AMD Ryzen try to always use 2 dimms to get memory you need. Using 4 can lose speed. If that matters you. In the end most people could not tell without testing.

DDR4 overclock might still be fine with 4 DIMMs (but 2 DIMMs still preferred)

About memory timing (for DDR4 at least, DDR5 might be similar) I suggest watching the following video

I built a 5950X system with 128GB (4 x 32GB) DDR4 because I wanted a maxed-out system on memory. It’s working fine but it’s only running at 3200MT/s. On DDR5 builds I’ve put together so far I’ve gone for 2 x 32GB because that gets you the most stable config if you’re contemplating memory overclocking (and even if you aren’t), and there are quite a few reports around about newer CPUs, particularly the AMD ones, not having such strong memory controllers as with the DDR4 boards. Overclocking boards like the MSI Unify X only have 2 DIMMs to promote the most stable signals at higher clock rates.

I’d go for 2 x 32GB.

1 Like

yeah mate i would take all that with a pinch of salt…
theres a few things i see as odd.
first he’s running a 12th gen which tops out at 3200 for quad channel support and 4800 dual channel…
meaning once you go over 3200 your reduced to 2 dims per channel and after 4800 1 dim per channel and t2 timings on both.

yet he shows 6400 t1 timings in quad channel.

next his numbers dont add up…

RL = CL *2000 / DR

  • Where RL is the ram latency (nanoseconds)
  • CL is the CAS latency (CL)
  • DR is the data rate (MHz)

To calculate RAM latency, multiply the CAS latency by 2000 then divide by the data rate.

using this and using his numbers…
we plug it in and get…
rl= 28 x 2000/6400
gives an rl of 8.75
he shows a rl of 9.8
which is more indicative of rl = 28 x 2000/6200

while his cas 40 timings which he would not show.
should spit out an rl of 12.5=40 x 2000/6400
but he’s showing 8.8
which is more indicative of rl = 40 x 1333/6400

lastly the variance between 58 and 54?.
i would expect 0.1 variance run to run on stable ram. not 4 points. so looks to me like the ecc unit is working overtime to correct errors.

so yeah take it with a large pinch mate. :slight_smile:

I just bought Ram for my build that I am currently working on for my 5800X I went with 2 x 32gb kit 3600 from g.skill

If you’re in the US this may be price/performance leader: