Solution
2x8GB 3600MHz or 4x4GB 3000MHz for Ryzen 9 3900x?
2x8GB 3600MT/s CL16 is likely to be faster than 4x4GB 3000MT/s CL16 or even CL14. It makes more sense to buy 2x8GB 3600 anyway since if you add a second of the same kit, you will have a better chance at hitting up to 3466MT/s in 4x8GB with your Ryzen 9 3900X. The performance difference between 3466 and 3600 at CL16 will probably be about the same or 5-10% difference in favor of 3466MT/s. On my Ryzen 5 2600, I'm running 4x8GB at 3000MT/s CL14 and it's faster than at 2x8GB 3200 CL14 in everything I have tested by around 5% and sometimes higher.

In most situations, 2x8GB for Ryzen gaming systems is just a better option for stability and trouble shooting.
After a little digging around, it appears that using 4 channels of RAM on Ryzens (and especially the 3rd gen models) either causes problems or doesn't work at all. Initially, the Ryzen 3000 series did not have support for quad channel memory, but I'm not sure if this was rectified since then.

Dual channel should work best for you, especially at the higher 3600MHz speed vs 3000MHz (assuming CAS latency is the same on both the models you're looking at)
 

andreiiwnl

Prominent
Oct 15, 2018
14
1
515
2x8GB 3600MHz

Ryzen is dual channel, regardless if you have 2 or 4 sticks.
Since ram must be matched, a 2 stick kit will usually be cheaper than a 4 stick kit of the same specs and capacity.
And,in this situation, you will have faster ram.
I've seen that even tho quad channel isn't supported, having a 4x4 kit makes your fps more stable and your 1% lows are higher. That's why i've been thinking of getting a 4x4kit. I found a HyperX 4x4 kit rated at 3200MHz 16-16-16-35 CAS for 15$ cheaper than the 2x8 kit 3600mhz 18-20-20-28 CAS
 
I've seen that even tho quad channel isn't supported, having a 4x4 kit makes your fps more stable and your 1% lows are higher. That's why i've been thinking of getting a 4x4kit. I found a HyperX 4x4 kit rated at 3200MHz 16-16-16-35 CAS for 15$ cheaper than the 2x8 kit 3600mhz 18-20-20-28 CAS
Where did you see that?
Can you give me a link?
I am doubtful and would like to check that out.
 
Thank you for the link.
I found it interesting.
There is evidently a small difference.
The frame rates I saw were all so high that I doubt one could tell the difference.
I don't know that the difference is compelling enough to go one way or the other.
I don't know if it sheds light on your original question.
3200 speed at cas 16 should be close to 3600 at cas 18.
ryzen performance seems to be closely tied to ram speed.
 
2x8GB 3600MHz or 4x4GB 3000MHz for Ryzen 9 3900x?
2x8GB 3600MT/s CL16 is likely to be faster than 4x4GB 3000MT/s CL16 or even CL14. It makes more sense to buy 2x8GB 3600 anyway since if you add a second of the same kit, you will have a better chance at hitting up to 3466MT/s in 4x8GB with your Ryzen 9 3900X. The performance difference between 3466 and 3600 at CL16 will probably be about the same or 5-10% difference in favor of 3466MT/s. On my Ryzen 5 2600, I'm running 4x8GB at 3000MT/s CL14 and it's faster than at 2x8GB 3200 CL14 in everything I have tested by around 5% and sometimes higher.

In most situations, 2x8GB for Ryzen gaming systems is just a better option for stability and trouble shooting.
 
Solution

Math Geek

Titan
Ambassador
with 4 sticks you also start running into issues with dual rank vs single rank ram and other issues. that's not just ryzen but many motherboards for both amd and intel.

check the manual and see what it says about 4 sticks vs 2. likely there will be some specifics about what you can run in all slots that won't be there with 2 sticks. overall for this and the reasons listed above, the 2 stick solution is just easier to work with and plenty good enough for the average gamer.