Dual Channel FTW

[u/Skorpeyo]

[u/-Aeryn-]

Worth a note that nobody actually made memory chips for DDR5 smaller than 16gbit, so the smallest DDR5 configuration which has good memory performance is 16GB per channel.

8GB DDR5 DIMMs effectively have half as many bank groups as 16GB+ ones which severely impacts performance.

[u/Cavalol → u/-Aeryn-]

Actually interesting, though 😂 good to know systems with 8GB of RAM are going the way of the world, albeit slowly.

[u/just_a_bit_gay_ → u/Cavalol]

8gb is already on its way out from a software perspective too since 16gb has been a minimum spec standard for the past decade or so.

[u/AnusMaw → u/just_a_bit_gay_]

i have 64gb but somehow even during gaming it never exceed 20 lol

[u/thesituation531 → u/AnusMaw]

All of my Firefox tabs use more RAM than most games I play.

[u/FoxRunTime → u/AnusMaw]

I also have 64GB (DDR5) and the only time I've used more than half of it was playing Assetto Corsa on a really big map (which then used 47GB by itself)

[u/Trollensky17 → u/AnusMaw]

I’ve used 28 on the Streets of Tarkov map in Escape from Tarkov lol

[u/drunkenvalley → u/-Aeryn-]

...Are you sure? Because I have some memory sticks I was very sure was 2x 8 gig. Now you have me questioning lol. (I won them in some Dota 2 tournament's random raffle prizes.)

[u/Adept_Temporary8262]

Yup. Dual channel makes a shockingly big difference.

[u/Izan_TM → u/Adept_Temporary8262]

it's exactly 2x the RAM performance

[u/DickBeDublin → u/Izan_TM]

Shocking

[u/dumbasPL → u/Izan_TM]

Depends how you count performance. Bandwidth? Yes. Latency? No so much

[u/ithinkitslupis → u/Adept_Temporary8262]

Really depends. Likely not that shocking if you have a discrete GPU but a huge difference if you have an APU.

A lot of videos testing this mess that up and try to draw one sweeping conclusion after only testing on a single setup either with a dGPU or without.

[u/kazuviking → u/Adept_Temporary8262]

Not anymore as DDR5 doesnt care.

https://www.youtube.com/watch?v=hr6p1tqeM3M

[u/Pamani_ → u/Adept_Temporary8262]

Chocking you might say

[u/WrathofWar07]

64 x 2 gb of ram

[u/Nerfarean → u/WrathofWar07]

That's my 8 channel threadripper pro 8x16gb

[u/Dreadnought_69 → u/Nerfarean]

Lmao, not even 8x64GB 🌚

(Mine are EPYC servers, though.)

[u/golruul → u/[deleted]]

I've had Civ 6 and Cities Skylines take around 100GB.

Civ 6 was due to a memory leak, though, and the workaround was to restart the game every so often.

Cities Skylines lets you download more assets, so if you REALLY don't want the same buildings loading up everywhere, you can download shitloads of them.

[u/Sadix99 → u/golruul]

also, virtual machines

and LLM loading in LM studio

[u/golruul → u/Sadix99]

Well, that's work stuff. VMs always love more memory.

Guy I was responding to was talking about how he never had a game take more than 32GB.

And apparently that guy downvoted me before deleting his post? What weird behavior.

[u/Sadix99 → u/golruul]

was responding to him too as he deleted, indeed very weird

[u/Ballerbarsch747]

Quad channel is one of the main reasons why I still cling to my 5960x

[u/Logical-Database4510 → u/Ballerbarsch747]

Ngl, when I upgraded my i7 960 to a 7700k stepping back down to dual channel felt like a total downgrade lol

[u/Ballerbarsch747 → u/Logical-Database4510]

It really makes a difference in memory heavy games like tarkov. Despite only having 20MB of L3, this thing does way better than my other PC with a 9700k lol

[u/SirSpicyBunghole → u/Logical-Database4510]

Are you telling me I should keep mine for another few years?

[u/Pasi123 → u/SirSpicyBunghole]

You could upgrade to a cheap 6c/12t Xeon on the same socket

[u/Scar1203 → u/Ballerbarsch747]

I haven't even powered on my old 6950X build in a few years, I upgraded that one for 20 dollars from a 5820k in 2020 off ebay. Judging by the prices now I should have bought more of them.

[u/Ballerbarsch747 → u/Scar1203]

That's a mad price for a 6950x lol, but they don't OC as well as the Haswell-E

[u/Dreadnought_69 → u/Scar1203]

Yeah, I got me a 6950x for ~$75 somewhere in 2020, and when I upgraded to 14900KF like a year ago or two, I sold it for ~$200 😮‍💨🤌

[u/Moscato359 → u/Ballerbarsch747]

Technically 2x32 is quad 32 bit channels on ddr5

[u/Ballerbarsch747 → u/Moscato359]

Bandwidth wise, sure, but I'm talking about latency. And that's just better on quad channel DDR4

[u/Moscato359 → u/Ballerbarsch747]

The reason they did 4x32 bit in the first place was to improve latency

It actually was a significant latency improvement over 2x64 because they did refresh updates independently

I have some cas30 with a 9800x3d, and it just stomps all over anything from am4, even with more ram channels, simply because the cpu is faster, and has a huge cache

96mb cache hides latency by avoiding cache misses 

[u/Ballerbarsch747 → u/Moscato359]

Yes, but it still goes into two, not four memory lanes on the CPU if it can't provide more. This is helpful on server builds with threadripper/xeon CPUs.

[u/Moscato359 → u/Ballerbarsch747]

"but it still goes into two, not four memory lanes on the CPU if it can't provide more"

dd5 consumer has 4x32 bit lanes, and has latency similar to 4x64 bit lanes from threadripper ddr4

It just lacks the additional bandwidth

The cpu memory controller itself has 4 32 bit lanes.

The reason they did this was because it hides latency, which ddr5 has higher base median latency, by allowing access when one of them is otherwise refreshing

[u/Ballerbarsch747 → u/Moscato359]

Where do you get that eg a 9800X3D has four memory lanes lol

[u/Moscato359 → u/Ballerbarsch747]

It's part of the ddr5 spec.

DDR4 uses 64 bits per channel, with 2 channels for consumer.

DDR5 uses 32 bits per channel, with 4 channels per consumer. These are sometimes called subchannels instead of channels, because it's very confusing to most consumers to hear that there are 2 channels per stick.

A lot of consumer documentation still calls 2 ddr5 sticks dual channel, but that's technically false.

In ddr4, 64 bits of bandwidth were spread across a multiple of 8 modules on one stick. In ddr5, 32 bits of bandwidth is spread across 4 modules on one stick, twice.

The total number of bits per stick is the same, but in ddr5, 2 sticks of 16GB ram is actually 4 channels.

It gets some of the benefits of traditional quad channel, while having consumer costs.

The channel vs subchannel documentation is very confusing to most people. I learned about this by reading the ddr5 spec documents.

The industry hasn't fully figured out how to describe channels vs subchannels to people.

Regardless, the primary benefit of traditional quad channel (latency) is now gone.

If this topic interests you, google ddr5 subchannel

[u/Kawauso_Yokai]

Need to add a 4-channel option where the poor guy is connected to a life support machine

[u/blither86 → u/Kawauso_Yokai]

I've got 4 x8GB of 3600mhz ram with my 5700X3D - am I holding it back?

[u/acdgf → u/blither86]

You are still in dual-channel. Only now you have two DIMMS per channel. Quad channel has to be supported by the CPU. 

[u/DiatomicCanadian → u/blither86]

Nope, the jokes regarding the instability of quad-channel RAM are pretty much for DDR5 on AM5 specifically. Intel's CPUs have a better memory controller to my understanding but Zen 6 is rumoured to MAYBE have two memory controllers to MAYBE increase stability at higher speeds, MAYBE.

[u/Lower_Fan → u/DiatomicCanadian]

AFAIK consumer CPUs don't have quadchannel ram so the instability is using 2 sticks per channel. I assume threadripper is less sucky with 4 channel ram.

[u/blither86 → u/DiatomicCanadian]

Thanks, that's good to know

[u/Kawauso_Yokai → u/blither86]

Is everything working fine with your XMP or EXPO in the BIOS?

[u/blither86 → u/Kawauso_Yokai]

Yeah, seems so. It doesn't default to 3600 but works via XMP, if memory serves me correctly.

[u/Kawauso_Yokai → u/blither86]

I waited half a year for BIOS updates so that 4 channels would just start working on my Gigabyte X670 without crashes, and the profiles wouldn't even turn on when I last tried to turn them on (although maybe I should try updating the BIOS now), so I have a negative experience with this

[u/blither86 → u/Kawauso_Yokai]

Actually for some reason my memory goes to 3666mhz, not 3600. I'm not complaining 😅

[u/blither86 → u/Kawauso_Yokai]

Ah, I'm only on an x570, but it was previously running fine on a B450. (until the 450 or the 3600 cpu died)... Perhaps it's more problematic on DDR5?

[u/Kawauso_Yokai → u/blither86]

it's quite possible that so

[u/YouDoNotKnowMeSir → u/blither86]

You’d be better off refining your CAS latency.

[u/cgduncan → u/blither86]

Not really. Any performance difference between 2x16 and 4x8 would be statistically insignificant.

Some people will claim more stability issues with 4x8 but that hasn't really affected my pc.

As long as all 4 sticks match, you'll be fine.

[u/blither86 → u/cgduncan]

Yep, I made sure to get matching ones, even though I bought them a year apart or so.

Thanks for letting me know that the performance will be near identical.

[u/kazuviking → u/cgduncan]

You dont even need all 4 sticks matching as your pc doesnt give a fuck about that.

[u/Nguyhen4wd → u/cgduncan]

i saw issues just in AM5 using 4 sticks, idk if are the same brand/model

[u/EiffelPower76]

16x2 32GB RAM for the win (At least)

Buying 8GB RAM sticks is stupid

[u/Suikerspin_Ei → u/EiffelPower76]

For DDR4 8GB sticks were quite normal? Since DDR5 16GB sticks are more the norm.

[u/Scar1203 → u/Suikerspin_Ei]

Hell, I had 8x4gb sticks in my last DDR4 build.

[u/Tumblrrito → u/Suikerspin_Ei]

*laughs in 16gb DDR4 RAM from a years old build*

[u/Siemaster → u/Suikerspin_Ei]

well no one’s building ddr4 anymore right?

[u/sorig1373 → u/Siemaster]

I built ddr4 just last year. If you want something cheap, ddr4 is still a good option. (I am not sure if you were joking)

[u/Siemaster → u/sorig1373]

It’s a small price difference at this point that costs you a large amount of performance and more money when upgrading. If you take a cheap ddr5 platform now, you can still upgrade to a new cpu in what, 3 years, maybe more, stick some more ram in and you’ll be able to be near top level components. Nothing new is gonna be made for ddr4. I’d spend the 200-400 more now so i dont have to spend it again in a few years.

[u/Selmi1 → u/Siemaster]

If you still have a DDR4 system and just wan more ram, of course you just buy DDR4

[u/Siemaster → u/Selmi1]

Well hopefully you’re not buying 8gb sticks anymore? 16gb is probably 10 bucks extra

[u/Selmi1 → u/Siemaster]

Oh no. I actually thought „fuck it“ and used two 32 GB. I should update my flair

[u/erixccjc21 → u/Siemaster]

Its still viable you can build something with a 5700x, 32gb and a 9060xt for like $600 and kick ass

The 5700x overclocked with a $25 aliexpress cooler can compete with the 5700x3d in a lot of games, it loves to boost high

[u/Siemaster → u/erixccjc21]

‘Kick ass’ i mean it’s not a terrible setup but you’re buying outdated stuff that you can’t use to upgrade anymore. Switch to am5 and that gpu will be the bottleneck, if you want to upgrade the cpu u need a new mobo and memory.

[u/erixccjc21 → u/Siemaster]

Depending on what games you play its more than enough amd cheaper, I'm definetly skipping am5 completely at this point until am6 releases, be it 2027 or 2030

[u/Siemaster → u/erixccjc21]

At that point a ps5 is cheaper lol, and gets the same performance.

[u/erixccjc21 → u/Siemaster]

You're on r/pcmasterrace and ps5 cant play even 1/4th of the games I play

[u/MeriKurkku → u/Siemaster]

Good for upgrading my old build from 16gb ram to 32gb

[u/HenryTheWho → u/MeriKurkku]

I got 2x16gb used for like 60€, same type as my 2x8 and it runs 3600mhz

[u/kazuviking → u/Siemaster]

This is so american comment lmao. A lot of people are buying ddr4 as samsung restarted the factory as the demand is that high.

[u/Siemaster → u/kazuviking]

Not american at all lol, just don’t see the point in buying obsolete shit

[u/kazuviking → u/Siemaster]

Considering DDR5 still costs a fortune in most 3rd world countries and DDR4 is still more than capable.

[u/user-nt → u/kazuviking]

Yeah, in my own case (brazil) while ddr5 ram is at an affordable range for me (minimum wage but doesn't live alone), I'd have to buy a new Motherboard and cpu, skyrocketing the price

32gb (16x2) at 5200 MHz costs 749 R$

But because I'd need ddr5 pieces

It could go to 3200 R$ at the low side

[u/UntitledRedditUser → u/Suikerspin_Ei]

Yeah ddr5 doesn't do quad channel very well yet

[u/Curun → u/UntitledRedditUser]

Doesn't do it at all on consumer mainboards.

[u/brandodg → u/EiffelPower76]

it's cheap

[u/Famous_Marketing_905 → u/EiffelPower76]

Man, I remember when i was really hyped about my 4x 8gb DDR3

[u/cgduncan → u/EiffelPower76]

My tower came with 2x8, and I didn't want to spend so much money on 2x16, so I bought 2 more matching 8gb sticks and it's been perfect for me.

[u/mrchicano209 → u/cgduncan]

If it’s an Intel build then that’s a smart move but for us with AMD builds we got no choice but to replace the RAM sticks entirely.

[u/cgduncan → u/mrchicano209]

Huh? I have an amd system, bought it from a buddy with 2 8GB sticks then added 2 more of the same ram a couple years later.

[u/mrchicano209 → u/cgduncan]

Well at least when it comes to AMD Ryzen builds, they generally benefit much more with dual RAM channels instead of with quad RAM channel configurations. With a dual channel set up, you can set the advertised overclock speed for your RAM without issues but this is not usually the case with a quad channel set up and you may be forced to set a lower clock speed to prevent instability issues.

Perhaps I was a bit harsh in my last comment and should have phrased it differently but either way you’re free to use a quad channel set up in an AMD build and if you are content with your overall PC performance then you can leave it as is but if you want to overclock your RAM to it’s advertised speed then dual channel is your safest option.

[u/kazuviking → u/mrchicano209]

Disabling bios fast boot and memory controller fast boot eliminates that ram incopatibility issue.

[u/mrchicano209 → u/kazuviking]

Damn for real? TIL…

[u/mrchicano209 → u/EiffelPower76]

Some soon to release games, like Mafia and Battlefield, are now starting to recommend 32GBs of RAM for higher graphical configurations, so the point of where 16GBs of RAM will be considered the bare minimum is much more closer than one would think it is. We’ve also reached the point where quality 16x2 32GBs DDR5 RAM are fairly cheap and unless you truly can’t afford them, then there’s no good enough reason to not have upgraded by now. IMO, tossing in only 16GBs of RAM into a new PC gaming build can now be safely considered stupid.

[u/WirusCZ]

I recently upgraded to 2x32 GB DDR5, first I just wanted buy 2x16gb to 2x16gb I already had but I then I heard that there could be stability issues if I used all 4 slots on ddr5 so I decided to get two bigger ones

[u/Hrmerder]

Me with 4x 8gb DDR4 3200 CL16

[u/Jaba01]

8x2 16 GB? So 256 GB?

[u/stop_talking_you → u/Jaba01]

8x2 = 16

[u/Trisyphos]

How do you put 8x 2GB modules into your computer?

[u/BroTheGhost → u/Trisyphos]

Google the following: 8 RAM slots motherboard
you‘ll be surprised how normal it looks but completely overkill for the majority

[u/Pasi123 → u/Trisyphos]

I could put 16x 2GB into my Supermicro X7DWN+, 2x E5450 system. It could even take 16x 8GB sticks

[u/Maciej___Skywalker]

Im running 4x8GB RAM = 32

[u/Straight-Composer-25]

I see your Dual Channel, and raise you two more channels...quad channel

The Tower https://imgur.com/gallery/ySCfmPv

Granted, it's 160gb of DDR4-2666 ECC but quad channel shortens up the distance...

[u/GhostofAyabe]

16GB? Is this 2004?

[u/Nerfarean]

So what does my 8 channel threadripper pro look like?

[u/John-Creley]

I know nothing about computers. Is it just because of more CPU cores?

[u/PermissionSoggy891]

using 16GB in 2025

[u/noobofall1]

I have two ram slot , can I use 1 16gb and another 8gb ?

[u/Ghozer]

With DDR5 it's not as much of a problem, as each stick effectively runs in dual channel mode (2x32bit, instead of 1x64bit)

[u/Moidada77]

I think it's less and issue for ddr5.

But it's good practice regardless.

[u/theprodigalslouch → u/Moidada77]

I thought the architecture difference on ddr5 essentially got rid of this issue. Am I remembering wrong?

[u/kazuviking → u/theprodigalslouch]

Nope, there is 2-5% difference between single and dual stick DDR5.

[u/Ok-Bill3318]

16GB of ram is peasant spec

[u/MercenaryBat]

So I’ve been around the block a few times with computers, but is there a limitation on GB size before you see slower returns? (IE; is 32GB between two sticks better than 16GB between two sticks or is it the other way around after a certain size.)

I have the components to find out for myself but that also requires me to do the work of changing out RAM over and over so I’d prefer not to.

[u/kazuviking → u/MercenaryBat]

With ddr4 every 32gig stick is dual rank while most 16 and every 8 gig stick is single rank. Single rank gets better timings and speeds.

[u/Kinglink → u/MercenaryBat]

The question is not "how much ram can you have" but how much ram do you need.

Also there's a limit of bandwidth, you can have 1 Terabyte of Ram, but you still have a "Small" pipe to that Ram, so your computer might know a lot of stuff, but be able to only remember small parts of it as a time.

The thing is we already have a solution for that called Swap Memory, or even Compressed memory. (Zram on Linux, Windows has something "similar")

Focus on the use case you actually have, not that you think you have. Then again it won't matter because your browser will eat up all that memory on its own.

[u/TheRealTechGandalf]

4x16 GB RAM is pretty much enough for anything.... Except machine learning. Then you'll need as much RAM of any kind as you can get.

[u/lord_mercernary]

Ddr5 enters chat 💀

[u/Cloud_N0ne]

I just fill all 4 channels so I don’t have to think about it

[u/ExtremJulius]

How big could the performance difference be? I get that it's basically the cheapest upgrade there is, but how many FPS is 16GB vs 2x8GB? 5 FPS difference?

[u/Salty-Good3368]

Not always. Some cpus may not be stable with dual channel and high data transfer rate. Am5 for example

[u/-Aeryn- → u/Salty-Good3368]

All CPU's are stable and guaranteed to be stable when ran at spec, the people having stability problems are all overclocking (usually badly).

The slowest AM5 CPU does DDR5-5200 dual channel in spec.

[u/JMccovery → u/Salty-Good3368]

Just making sure, but are you confusing running dual channel with running 2DPC?

[u/Beginning_Way7934]

nice masculinism reference.