[SOLVED] 2x16gb vs 4x8gb for 3900x

corndog1836

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i have a 3900x with a 32gb 2x16gb kit(Model F4-3600C16D-32GTRS ) oc'd and tuned to 3800mhz 14,14,14, 28 1t command rate @1.49v and FCLK is 1900. . i know it is dual rank and i have it in dual channel slots on crosshair viii board(slots b2 and a2 from the manual) . Am i to understand that a 4x8 kit of same speed and timings would be faster? just saw Gamers Nexus and Hardware unboxed video suggesting that is the case .
 

corndog1836

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True, they found that 4X8GB is from 1% to 10% better than 2x8GB, also they said 2x16GB is way better.
Not sure a all why but this is mainly because the rank configuration.

Basically Ryzen CPUs performs better when you put in it
2 dual rank modules
or
4 modules any type

Not sure if either speed or latency are factors to count but better results were given by 3200MHz CL14 or 3600MHz CL16 configs
thank you i have 2x16GB 3800 14-14-14-28 CR1 @1.49v FCLK= 1900mhz and yes they are 128bit dual rank.... i can only get them to 62ns latency(beleive this is good) so from what you are saying i already have the best confog for my 3900x @ 4.5ghz all core @ 1.35v . THANK YOU!!!
 
Reactions: pmz94
It's a bit more complicated, but essentially when using at least a Ryzen CPU and Ryzen platform motherboard with dual rank ram configurations, 2x16GB allows for better overclocks than 4x8GB when using a daisy chain ram slot trace topology. Most motherboards use daisy chain topology, but there are also boards with T topology. T topology will lower the maximum overclock potential, but can allow for higher overclocks with all slots filled compared to daisy chain with all slots filled.

Dual rank 2x16 or 4x8GB should always be faster than 2x8GB with the same speed and timings on Ryzen motherboards. 2x16GB should allow for slightly better overclocks and tighter timings than 4x8GB with daisy chain topology.

Edit - I should also say that 2x8GB is usually only around 5-10fps slower than 2x16GB or 4x8GB in games that gain any benefit from dual rank configurations. Some games may gain as much 15-20fps, but that would usually be with already high fps.
 
Last edited:
Sep 16, 2020
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Am i to understand that a 4x8 kit of same speed and timings would be faster? just saw Gamers Nexus and Hardware unboxed video suggesting that is the case .
True, they found that 4X8GB is from 1% to 10% better than 2x8GB, also they said 2x16GB is way better.
Not sure a all why but this is mainly because the rank configuration.

Basically Ryzen CPUs performs better when you put in it
2 dual rank modules
or
4 modules any type

Not sure if either speed or latency are factors to count but better results were given by 3200MHz CL14 or 3600MHz CL16 configs
 
Last edited:

corndog1836

Distinguished
Mar 31, 2010
1,768
5
20,165
150
True, they found that 4X8GB is from 1% to 10% better than 2x8GB, also they said 2x16GB is way better.
Not sure a all why but this is mainly because the rank configuration.

Basically Ryzen CPUs performs better when you put in it
2 dual rank modules
or
4 modules any type

Not sure if either speed or latency are factors to count but better results were given by 3200MHz CL14 or 3600MHz CL16 configs
thank you i have 2x16GB 3800 14-14-14-28 CR1 @1.49v FCLK= 1900mhz and yes they are 128bit dual rank.... i can only get them to 62ns latency(beleive this is good) so from what you are saying i already have the best confog for my 3900x @ 4.5ghz all core @ 1.35v . THANK YOU!!!
 
Reactions: pmz94

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