How much does Ryzen benefit from dual-channel memory?

STIHL

Distinguished
Aug 31, 2013
131
0
18,680
I currently have 1x8GB DDR4 2400MHz for my R5 1500x. I am planning on upgrading my RAM and also overclocking as i understand Ryzens infinity fabric benefits greatly from clock speeds. obviously, i am on single channel now, and i want to get another stick to get 16GB dual channel, however, that is £85 (gone up £25 in a couple of months) and i don't actually need 16GB, just a little over 8. I was thinking of saving £40 and get another 4GB and run it in single channel. I won't see a performance increase unless i go over 8GB, i know that already. But is the performance increase to dual channel really worth £40. From what i have seen in benchmarks, it is very marginal, only a few FPS in games (playing games is the most demanding task i do on my PC). However these benchmarks were not with Ryzen. Would the performance increase from single channel to dual channel on ryzen warrant the extra £40? Is the performance increase bigger on ryzen than other CPUs, like the clock speed? What do you reccomend?
 
Solution
ryzen benifits the most from dual channel and high mHz, the reason is its unique architecture.

its cores are paired to work on 1 memory allocation (so technically it has the stated number of cores, but practically you should halve this figure!) - this has an advantage and disadvantage. obviously the disadvantage is that 2 cores work on 1 instruction/problem unlike intel where 2 cores can work on 2 instructions/problems.
BUT because of the pairing, that single instruction gets 2 cores worth of power in a ryzen ... greatly speeding up the time taken to process that data. .. this leads to the cpu requesting more data from your RAM .... QED. more RAM throughput = happy ryzen.

so yes, ryzen loves dual channel, ryzen loves high mHz, it...
ryzen benifits the most from dual channel and high mHz, the reason is its unique architecture.

its cores are paired to work on 1 memory allocation (so technically it has the stated number of cores, but practically you should halve this figure!) - this has an advantage and disadvantage. obviously the disadvantage is that 2 cores work on 1 instruction/problem unlike intel where 2 cores can work on 2 instructions/problems.
BUT because of the pairing, that single instruction gets 2 cores worth of power in a ryzen ... greatly speeding up the time taken to process that data. .. this leads to the cpu requesting more data from your RAM .... QED. more RAM throughput = happy ryzen.

so yes, ryzen loves dual channel, ryzen loves high mHz, it wants data shoved down its throat so it can gobble it up.
 
Solution


just another question, when i first got my ram, my mobo downclocked it to 2133. should i put my ram back down to that before adding the other 8, then put them both back up?
 
your mobo/cpu have RAM speed caps, your RAM is down clocked to the lowest cap (of the two) to ensure stability. intels is 2400 i believe. i dont own a ryzen so i am unsure what it is. to be honest i would always suggest you get 3000 in a pair 2 x 8GB or 2 x 4GB for ryzens. if it downclocks, no problem, but if it can reach 3000 in dual channel mode = youre laughing.
 


Well, i have already got 2400MHz, and i don't want to get another 16GB @3000 or 3200 because that will cost a fortune. The question was, when installing new ram should i clock it to the lowest cap before adding the new ram, or just put it in?
 
you should buy a matched pair tbh, but as you already got 1 stick, you should buy another at the same speed to help with compatibility, the mobo will clock it automatically.

cant garantee that both sticks will work together, i am sure you are aware.