If i have 3x8gb = 24gb on a dual channel mobo, is it still dual channel?

[SoNic67]

I'm with the "buy close enough chips" group here too. You don't need binned chips anymore today, that's from a decade ago.
Personally I run a Quad channel with equal size memory sticks, but two channels use single rank chips, and faster and the other two channels use dual rank and slower. The frequency is selected to match the lowest. Single rank and dual rank have to be on separate channels, and start filling slots with white and further away from CPU. That's all I need to care for my motherboard and Intel CPU.

 

[Bill_Bright]

p.s. - The unused memory is actually used as disk cache, but for that the single-channel speeds are WAY more than enough.

Ummm, no it's not. It is just used as slower RAM. The CPU may use it to temporarily store (cache data), or it may use it for something else - but that is totally different from a disk cache.

What you see in task manager as Cached is not the same thing at all as a disk cache. A disk cache, by definition, is a mechanism used to improve the time it takes to read from or write to a disk drive.

That "cached" value show in Task Manager is exactly what it says it is when you hover over it. It is "Memory that contains cached data and code that is not actively in use."

If you open Resource Monitor and check the Memory tab, you will see the "Cached" memory equals "Standby + Modified" - again, nothing to do with disk cache. Hover of Cached and you will see the following:

Cached: Amount of memory (including Standby and Modified memory) containing cached data and code for rapid access by processes, drivers and the operating system

Now if you hover over "Modified" you will see that tiny amount (just 181Mb on my 16GB system) is data waiting to be written to the drive - but that is not considered part of the system cache. That is just a method to keep the OS from going into a "wait state" while low priority data is saved to disk. That again, is different from a disk cache.

 

[R-T-B]

Do people seriously not remember ram based disk caching? Guess it was a bigger tunable item in the dos days...

Anyways, it's a thing. I guess you could argue it's not a "disk cache" in the strictest sense of the word, as it's not on the disk, but it is a cache, in memory, of your HDD contents. This is splitting hairs really lol as the end result is the same: Queries to what would've hit the HDD platter are answered faster.

 

[Bill_Bright]

Do people seriously not remember ram based disk caching?

Who said anything about not remembering something?

Just because something is a cache, that does not mean they are all the same. Most CPUs have 2 or 3 built in caches. The Page File is considered a cache. The built in memory on disk drive controller boards - often called buffers - are caches.

The point here is, don't confuse unused system RAM with a RAM Disk. They are not the same thing. Unused system RAM is just that. It is NOT cache memory. That has to be manually setup to act as such and then it becomes dedicated for that use, and is unavailable to be used as regular system memory.

Unused system RAM is available, if needed. It is NOT automagically used as a disk cache as was claimed. It is simply unused.

 

[Gasaraki]

For x58 boards, 2 or 3 sticks will get you dual channel. At least the EVGA one I dove into.

Wow, so much fud in this thread. I'm running a X58 right now. 3 sticks ill give you triple channel. That's the whole point... 6 sticks will be triple channel also.

 

[R-T-B]

The point here is, don't confuse unused system RAM with a RAM Disk. They are not the same thing. Unused system RAM is just that. It is NOT cache memory. That has to be manually setup to act as such and then it becomes dedicated for that use, and is unavailable to be used as regular system memory.

With SuperFetch and similar things in modern kernels that is really not so true anymore. The OS considers unused ram "wasted" and caches as much as possible with the idea it can (and often is) rapidly freed for immediate use.

 

[phanbuey]

But I guess the new Ryzens are smarter and doing a similar approach as modern Intels...

Maybe with a good motherboard, but by default my Ryzen's approach with an ASUS B350 to this is to either refuse to post, or put the odd stick in "hardware reserved" and not be usable.

 

[Jetster]

It depends on the board but there is a Dual Channel Asymmetric that will run different sticks as dual channel. I had a Dell laptop that was like this.
maybe its possible if the board support it to run three. Exactly how it does it, not sure

 

[EarthDog]

https://www.compuram.de/blog/en/single-dual-and-multi-channel-memory-modes/

 

[Sasqui]

Yes, that was incorrect. Triple vs Dual is correct. The speed difference between triple and dual isn't particularly noticeable. In theory, it sounds like it should be 30% faster, but in reality it's far from it.

 

[Berfs1]

Flex mode, where u flex to the world that u can run odd ram confíes lmao (it is actually called flex mode, which allows for more flexibility of ram configurations)

 

[Bill_Bright]

With SuperFetch and similar things in modern kernels that is really not so true anymore. The OS considers unused ram "wasted" and caches as much as possible with the idea it can (and often is) rapidly freed for immediate use.

Just a tiny bit of homework shows that is not even how superfetch works.

Superfetch works by learning how the user uses his or her computer, then preloads them into RAM. Not into "unused" RAM, and not as cached data, just loaded programs.

I'll say it again, unused RAM is just unused. If the OS uses it, it is now used RAM. That is NOT the same as RAM designated as cache.

 

[EarthDog]

Yes, that was incorrect. Triple vs Dual is correct. The speed difference between triple and dual isn't particularly noticeable. In theory, it sounds like it should be 30% faster, but in reality it's far from it.

In theory it should be 50% faster (adding 1 more to 2 things is 50% more). But as you said, it isn't.

 

[MrGenius]

FUD = Fear Uncertainty and Doubt. It's typically used to describe something that the truth is not yet known, or fully known, about. But a common human response to the unknown is often in the form of fear, uncertainty, and/or doubtfulness. Leading to statements, claims, or questioning which constitutes FUD. Which typically represents the worst possible assumptions. Such as those of a conspiratorial, conjectural, hypothetical, cynical, and/or pessimistic nature. However, just because a statement or claim is merely not true/false, or questionable, does not make it FUD. To be considered FUD it needs to manifest the aspects of the acronym. Is it based on fear, uncertainty, or doubt of the unknown? If so, it's FUD. If not, it's simply not true/false.

 

[R-T-B]

and not as cached data

I think you have a fundemental misunderstanding of what a cache is in basic premise.

It's in essence, copying something into a fast place for rapid access.

How is this not describing a cache?

Superfetch works by learning how the user uses his or her computer, then preloads them into RAM.

If you think it's executing the programs or something, you'd be wrong, anyhow.

So yeah, and I understand Superfetch on a better level than the simple consumer provided marketing description btw, so you can trust me on this one. Or not. It's your choice, I really don't care.

 

[Wavetrex]

I chose not to continue to argue with him about the subject of RAM usage, caches, preloading and the rest of the things.
His current knowledge of how CPUs, RAM and operating systems work seems to be a complete chaos and a spagetti of misunderstanding and false information. And a brick wall of stubbornness above it.

@R-T-B , perhaps you should back off as well and just let him believe whatever he wants to believe.

 

[king of swag187]

Curious, but would dual channel work in a way that say, I have 2 8GB sticks for 16GB (2x8GB=16GB) and a 16GB stick (1x16GB=16GB), so 32GB in total. If I put the 16GB stick in Channel A, and the two 8GB sticks in channel B, would dual channel work for a full 32GB of dual channeled memory?

 

[Shambles1980]

I'm with the "buy close enough chips" group here too. You don't need binned chips anymore today, that's from a decade ago.

i didnt bother back then either. i just changed the timings on all the ram to match the timings of the worst stck.

Curious, but would dual channel work in a way that say, I have 2 8GB sticks for 16GB (2x8GB=16GB) and a 16GB stick (1x16GB=16GB), so 32GB in total. If I put the 16GB stick in Channel A, and the two 8GB sticks in channel B, would dual channel work for a full 32GB of dual channeled memory?

not really how it works imagine that every stick of ram has a pipe connecting it to the cpu. and you can fit x ammount of data in that pipe per hz of the ram
(x2 in ddr because it can do the work on the peak and the trough in ddr) dual channel ram uses 2 sticks of ram and pretends that it is 1.. so it now has 2 "pipes" that way it can send 2x the data to the ram in the same time.
the third stick of ram only has 1 pipe.. and no stick to pair with to get a second one. so you cant send twice the ammount of data to it in the same amount of hz it just wont fit down the pipe..
but you can argue that 1 stick of ddr ram with more space and really tight timings may perform better than 2 smaller sticks with higer latency.

but thats a different discussion.

 

[R-T-B]

@R-T-B , perhaps you should back off as well and just let him believe whatever he wants to believe.

I have no desire or will to argue with him so no worries.

 

[Countryside]

Personally i would stick with 2x8 or 4x8 but is up to you.

 

[SoNic67]

every stick of ram has a pipe connecting it to the cpu.

More like highway lanes. One stick has 8 byte wide lanes (64 bits). Using two sticks in "dual channel" mode is like putting two of those highway lanes one next to another - for 16 byte (128bits) width. Now you have doubled the number of lanes, you can double the number of cars that can travel in that direction, at the same speed of travel (access).

 

[Bill_Bright]

I think you have a fundemental misunderstanding of what a cache is in basic premise.

It's in essence, copying something into a fast place for rapid access.

How is this not describing a cache?

Gee whiz! Please follow the context of the thread!

I never, as in NEVER EVER said the unused RAM cannot be used to cache data. In fact, I specifically said right from the start in post #27 above (my bold underline added),

The CPU may use it to temporarily store (cache data), or it may use it for something else - but that is totally different from a disk cache.

The point of dispute was a poster stating (again, my bold underline added) "The unused memory is actually used as disk cache". That is incorrect. It is not in any way used as "disk" cache. Nor is it, by default or automatically, used as "RAM based disk caching" as you suggested above - a RAM disk must be set up manually by the user.

Now if you are going to continue to suggest unused RAM is, by default, the same as a disk cache, then it is you who have a fundamental misunderstanding of how system RAM is utilized - as well as a fundamental misunderstanding of RAM Disks.

See: RAM Disks Explained: What They Are and Why You Probably Shouldn't Use One

I absolutely understand the basic premise of a what a cache is. But that is NOT what this discussion is about! So I say again, "Just because something is a cache, that does not mean they are all the same." Many network cards have built in RAM for buffering. Does that mean it is a "disk" cache? NO! Are L1, L2, L3 "disk" cache? NO! CPU cache is not the same as disk cache or RAM cache.

Bill: "Dogs are mammals, have 4 paws, fur, and a tail".
Fred: "That animal is a mammal, has 4 paws, fur and a tail".
R.T.B: "Then its a dog. Clearly Bill has a fundamental misunderstanding of the basic premise of a dog".



I'm done here.

(Edit comment: Fixed typo and spelling error missed by spell checker)

 

[R-T-B]

No worries bill. You don't need to get worked up. I just misunderstood your angle. Don't have as much time to read posts as I used to.

Your example is silly. As someone used to classful programing that's something drilled into me from day 1.

I also understand ramdisks well, used to set them up on OS/2 back a bit ago...

The point of dispute was a poster stating (again, my bold underline added) "The unused memory is actually used as disk cache". That is incorrect. It is not in any way used as "disk" cache.

I agree. I simply meant Superfetch caches disk based data.

 

[Bill_Bright]

Your example is silly.

It is not silly if you got the point - which it appears you finally did.

I just misunderstood your angle. Don't have as much time to read posts as I used to.

I fully understand and respect the fact time is limited. This is especially pertinent when it comes to all of us who volunteer what little free time we have to help others. With that in mind, to avoid such misunderstandings in the future, I might suggest finding the time to actually read and understand what someone is saying before accusing them of not knowing what they are talking about - as that will get anyone "worked up".

used to set them up on OS/2 back a bit ago...

Been there, done that too. I actually miss that OS, but that's for another discussion. And actually my first RAM disk experience was with the C64 and a Commodore RAM Expansion Unit years before OS/2 came out - but that's another discussion too.

 

[aMpeDuP]

you sure that's not some ram leak caused by software ?
I have 16gb too and I hardly remember it ever coming close to 14gb even though I'm used to running a game on one display,watching a stream on the other and having a dozen pages open at the same time.

The more RAM you have, the more Windows uses. Unused RAM is wasted extra performance. One wants to use as much RAM as possible, really - but still have enough free RAM ready to be used.

Only Chrome usually takes up ~ 5GB or more for me (multiple windows, many many tabs). So it all depends on how you use the computer and what. There is nothing strange about using 14GB.

Attached picture is when I'm not gaming or using any heavy software.