Question Why Quad Channel Memory much more expensive and no DDR4 3600 or 4000?

[Abormot]

My motherboard supports Quad Channel Memory - so I don't know should I go with Quad Channel Memory only or I can use Dual Channel kits.

NewEgg does not have DDR4 3600 Quad Channel Memory and DDR4 3200 is WAY more expensive comparing with Dual Channel? So, what is the point with this Quad Channel Memory?

I also do not understand what does mean DDR4 3600+(OC) - does motherboard support all above 3600? Or what? What does mean "+"?

 

[Phaaze88]

I can answer some of these...

-3600mhz isn't available? Different country? I literally just bought this kit from them: https://www.newegg.com/g-skill-32gb-288-pin-ddr4-sdram/p/N82E16820232881

-Not much point to it, it seems, unless you work in a datacenter. I'll post this quote:
"Despite the theoretical “RAM bandwidth doubling”, the only apps that will actually benefit from that are those where the processing is highly data-intensive, the rare apps with low L3 cache hit performance. Think working on huge independent data sets, a program with thight loops, so you’re constantly needing the RAM bandwidth to feed the CPU with completely new data, and the CPU spending most of it’s time asking for completely new data to process.
However, for most normal usage apps, even the latest games, the biggest benefit is getting bigger on-CPU L3 RAM caches, size if such RAM caches increase when going to a higher number of cores (those i9 CPUs don’t cost tons for no reason). Most of the time, your app’s “next bit of functionality or data” will nearly always come directly from the cache. The 1% of the time that you get a cache miss, THAT is when you’ll get twice the bandwidth, but 98% if the time, you get no benefit, because your RAM access remaining in on-CPU cache anyway, so you seem to see your overall performance go from 100% to 102%, not from 100% to 200%! So quad-channel is really a bit of a waste, for most people.
If you’re a professional working on on say meteorologic or seismologic data, go for quad-channel RAM. Otherwise, nope that “double your RAM bandwidth” won’t give you faster apps. At all. Going for more cores will."

-DDR4 3600+(OC) means '3600 or higher OverClock'. It's best to consult the motherboard manual - or even online manual - for compatible memory kits.

 

[Darkbreeze]

There is no such thing as dual channel memory, or quad channel memory or triple channel memory. There is ONLY, memory. Period.

Dual, triple, quad and other multiple channel memory configurations are an inherent part of the motherboard and the platform in general. There is no difference in the memory, at all, between "quad" or "dual" channel kits, EXCEPT for the fact that a quad channel kit comes with four sticks that have ALL been tested to be compatible with each other. THAT is important, because purchasing two separate kits with two sticks in each kit may NOT work together. They may, but they just as well may not. The only way you get any guarantee that four sticks are going to work together is if they are purchased in one kit because that means they have been tested for compatibility and have all come off the same assembly line at the same time and use the same components to build the module.


Two separate kits, even if they have the same part number, might be built using different components, with different ranks or rows or different memory chips (IC's).

If you want to run four sticks in a quad channel board, get a four stick kit. If you want to run 8 sticks, get an 8 stick kit. It is more expensive BECAUSE it is harder to get four or eight sticks to all play nice together than it is to get only two to do so. The more sticks there are, the more chances there are for discrepancies in compatibility from slight manufacturing differences or simply the law of averages.

 

[Darkbreeze]

Not to mention, these for example, are the exact same price as the same memory in a two stick kit, if you buy two sets. Both come out to exactly 189.98. Certainly that's not true for EVERY model, but it's equally not true that it isn't true for some models.

PCPartPicker Part List

Memory: G.Skill Trident Z RGB 32 GB (4 x 8 GB) DDR4-3600 Memory ($189.99 @ Newegg)
Total: $189.99
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2019-11-11 02:11 EST-0500

 

[Darkbreeze]

I can answer some of these...

-3600mhz isn't available? Different country? I literally just bought this kit from them: https://www.newegg.com/g-skill-32gb-288-pin-ddr4-sdram/p/N82E16820232881

-Not much point to it, it seems, unless you work in a datacenter. I'll post this quote:
"Despite the theoretical “RAM bandwidth doubling”, the only apps that will actually benefit from that are those where the processing is highly data-intensive, the rare apps with low L3 cache hit performance. Think working on huge independent data sets, a program with thight loops, so you’re constantly needing the RAM bandwidth to feed the CPU with completely new data, and the CPU spending most of it’s time asking for completely new data to process.
However, for most normal usage apps, even the latest games, the biggest benefit is getting bigger on-CPU L3 RAM caches, size if such RAM caches increase when going to a higher number of cores (those i9 CPUs don’t cost tons for no reason). Most of the time, your app’s “next bit of functionality or data” will nearly always come directly from the cache. The 1% of the time that you get a cache miss, THAT is when you’ll get twice the bandwidth, but 98% if the time, you get no benefit, because your RAM access remaining in on-CPU cache anyway, so you seem to see your overall performance go from 100% to 102%, not from 100% to 200%! So quad-channel is really a bit of a waste, for most people.
If you’re a professional working on on say meteorologic or seismologic data, go for quad-channel RAM. Otherwise, nope that “double your RAM bandwidth” won’t give you faster apps. At all. Going for more cores will."

-DDR4 3600+(OC) means '3600 or higher OverClock'. It's best to consult the motherboard manual - or even online manual - for compatible memory kits.

This though, is largely irrelevant if somebody HAS a quad channel board, because it's not going to be up to you what kind of configuration it decides to use. If you install four sticks in the correct DIMM slots, it is GOING to configure them in quad channel. There is no option to have two sets of dual channel sticks in a quad channel board unless you populate DIMM slots that cannot be used to achieve a quad channel configuration in which case, you won't end up with a dual channel configuration either most likely. Potentially on an 8 DIMM slot board you might be able to install four sticks in such a way that you end up with two sets of dual channel configured but I'm not sure why you'd even want to do that if the board and the sticks are all capable of quad operation.

But you are correct that the performance gains, will be minimal, and potentially not very noticeable. Still, it's there, and ANY gains we can get for free are generally welcome.

 

[Phaaze88]

No idea - it never even crossed my mind why anyone would want to do that... Oh right. Price... Probably shouldn't be on the HEDT platform, unless there's a specific reason?
It's there; you may as well use it...
Got a quad channel board, get quad channel memory.

 

[Darkbreeze]

I also do not understand what does mean DDR4 3600+(OC) - does motherboard support all above 3600? Or what? What does mean "+"?

There probably WEREN'T any memory kits above 3600mhz when those specifications were documented, and since they rarely if ever go back and make changes to the original specifications on the motherboard product page, they simply put 3600+ to indicate that when memory that is faster comes out, if it is supported, it too will be considered an "OC" which really ISN'T an overclock, it is just running outside of JEDEC default specifications at the XMP or DOCP or AMP profile speed and timings. Technically, an overclock. Realistically, it is simply assigning the correct profile for the memory kit based on its SPD EEPROM profile specifications that are hard coded to the sticks.

 

[gskill support]

Dual , Triple, Quad, etc. channel memory is such that the modules have been matched and tested to operate at the rated specifications together, on a particular platform.

Ie. dual channel for Z390 and X570, etc. in 8GB, 16GB, 32GB, and 64GB capacities

triple channel for X58, 12GB and 24GB sets.

Quad channel for X99, X299, X399, 8 module kits for 128GB

While the modules use same chips and are essentially 'just RAM', the specifics mentioned above are quite important when selecting a memory kit so for these reasons it is best use a memory kit type for the specific motherboard/memory architecture. Doing so ensures the user has the ideal memory kit for their build and most likely has been certified for use to operate at the rated specifications. Purpose of QVL, "For AMD", 'Quad Channel Memory', etc. is all meant to be more specific for the potential user. For example, an AMD user may be looking at DDR4-4400 memory that says For Intel and only has Intel motherboards listed for QVL, this should be some indication/warning that the RAM may not be compatible with their system. Commonly, frequency may be too high for the platform so if XMP Profile is not compatible, the combination can not be G.Skill QVL certified. However, it is possible the RAM can still work and operate at a lower frequency, but this is not always the case. It is always best to follow the G.Skill QVL to reach the rated specifications.

 

[Darkbreeze]

It is always best to follow the G.Skill QVL to reach the rated specifications.

This. So long as you do THIS, and the same applies to Corsair, Kingston, etc., you will minimize any possible potential issues.