DDR4 quad channel vs dual channel memory - just testing or other differences?

[JerryTheC]

I'm in the early stages of thinking about a new content creation PC build, where I'd eventually like to end up with a LOT of ram.
but since where I'd like to end up is going to be expensive, there's a lot to be said for starting off with a cheaper CPU and motherboard,
and then switching later.

Possible problem is that the final version would be 4 channel, while the cheaper one would be 2 channel.

I'd like to be able to swap ram between the two - so my question is, are there any differences between 4 channel RAM sets and
2 channel RAM sets other than testing the RAM in sets of 2 or 4 together? can you use a 4 channel set in a two channel system
(given enough slots) or vice versa? (If it makes a difference, I'm currently leaning towards an Intel rather than AMD CPU).

 

[thesmokingman]

That's just throwing money away. Build how it makes most sense. Going cheap now and replacing later is wasteful and invites issues later. And I don't know what content creation you're doing but going intel is really throwing money away.

 

[TheoneandonlyMrK]

I'm in the early stages of thinking about a new content creation PC build, where I'd eventually like to end up with a LOT of ram.
but since where I'd like to end up is going to be expensive, there's a lot to be said for starting off with a cheaper CPU and motherboard,
and then switching later.

Possible problem is that the final version would be 4 channel, while the cheaper one would be 2 channel.

I'd like to be able to swap ram between the two - so my question is, are there any differences between 4 channel RAM sets and
2 channel RAM sets other than testing the RAM in sets of 2 or 4 together? can you use a 4 channel set in a two channel system
(given enough slots) or vice versa? (If it makes a difference, I'm currently leaning towards an Intel rather than AMD CPU).

The timings are adjusted slightly for a quad channel set.
You could use just two for now.
Two Channel kit's have Xmp timings set for two.
This is mostly due to ranks, quite complex but most sticks are single rank so a dual channel kit presents a single rank to each of the CPUs memory controller, with four sticks your automatically dual ranking each memory controller plus interleaving really kicks in here.
You can buy two, dual channel kits but are best off not buying them separately, you want the same memory chips and manufacturer's change these or their batches a lot.
However two separate dualies are then not set up right for quad channel ,jedec ,slower speeds are still sure to work, Xmp likely won't, but it's possible to manually tune it but YMMV I am running two kits in quad at Xmp(speed manually) so I know I and others have done it.
Also the memory controller is also a variable in the equation, it will do what it will do.

 

[StormLightningSL]

You could buy a 4-channel kit and use it quite comfortably on a 2-channel motherboard with 4X RAM slots. Imo, it would work without any issues.

When you do upgrade to a better CPU and motherboard, the 4-channel memory would still work, based on the new compatibility. However, if you bought 2X 2-channel memory kits now, and later hope to run them at 4-channel performance, you may get hiccups. I'd suggest you go with a 4-channel memory kit right now, instead of 2x 2-channel memory kits now or later if your end-use is going to be in a 4-channel system.

 

[TheLostSwede]

With current RAM prices, buy as much RAM as you think you'll ever need (and can afford), as it's not likely to get any cheaper. Later this year the transition to DDR5 is going to start, which means DDR4 production will slowly decrease and prices will increase.

 

[Night]

Depends on your budget really, you could get Threadripper on a TR40 or TRX40 platform that uses quad channel, motherboards and Threadrippers aren't that much cheap to begin with, you can also go with Intel but I think Threadripper will be better value for your money. If you don't intend to use very intense CPU applications, you could go with Zen 3 that uses Dual Channel mode, 4 x 32GB kit should be good enough. If you will need more, you will have to opt for a quad channel because of current limitations to 32 GB per DIMM, unless you'll be getting server memory. DDR5 will introduce bigger sizes per module if you'd like to wait.

 

[ThrashZone]

Hi,
Memory is not created equally
B-die will usually be the best at adapting to different platforms
B-Die Finder

Dual channel boards do not work in quad channel just by filling all four slots unless you're referring to x99/ x299 platforms these are true quad channel boards on intel not sure which are quad channel on amd side ?
How a board/ cpu work with four sticks amd 5k series seems to do it well while intel it really depends how you use it
Four sticks will usually not oc as well as 2 sticks.

 

[Night]

not sure which are quad channel on amd side ?

TR4 and TRX40 platforms.