Can I use dual channel RAM - 4 identical kits to run it as a Quad Channel? AMD TR4

[ITFT]

Hi all,


I'm about to build a PC for my customer and since every penny is on the count, I could save some cash on the memory. The client needs 128Gb RAM, which is very pricey these days, that would be 8 modules. I wonder if I could use 4 identical dual channel kits in order to get 128gb Quad Channel in the end?

Also, what kind of motherboard would you recommend? The PC is not for gaming so anything to do with the graphics cards support is pretty much useless for this client, he could do with a single PCI-E Slot, but he needs a powerful CPU and 128gb RAM for the VMware.

Thank you.
Paul

 

[kanewolf]

Without a matched set of RAM, the best answer is "Maybe". Those four kits may work fine or may not. The benefit of a 128GB kit is that the memory vendor has taken the risk out of it working as a set. So how much risk can you tolerate?

 

[feelinfroggy777]

Mixing and matching RAM does not always work, even if it is the same model. This is why RAM is sold in kits as they are tested to work with each other. But just because it does not always work, does not mean it wont work either. I would make sure that the RAM is on the motherboard QVL list and get it from a vendor that accepts returns just in case it does not work.

Threadripper is a great CPU but it has real RAM compatibility issues, so when it comes to motherboards I suggest you look at RAM first and then find a motherboard where the RAM is on the QVL. All of the TR4 motherboards are expensive. They are all very highend. I have the Zenith Extreme and it is one of the more expensive TR4 motherboards. It was not my first choice, but I already had the RAM and it was the only board I could find that the RAM was on the QVL. So for me, it was worth the extra couple hundred bucks.

The Asrock Taichi is a good board for a good price, but the reality is with TR4, they are all good boards. There are no budget TR4 boards. Even if you get the cheapest one it is still a good board, so you really cant go wrong as long as the RAM is on the QVL.

 

[ITFT]

Thank you guys. The QVL is often has to be updated, so I agree it's a lottery, I asked for advice as this is a new build for me and indeed there are a lot of complaints about the TR4 RAM compatibility. The KIT I'm on about is supported by the motherboard, but the one I want to get is for the Dual Channel only - so just 2 sticks and if I get 8 of them in theory it should work as it's supported by the motherboard and the CPU manufacturers. Also this RAM (Crucial) works perfectly fine on the 1800X CPU, so I would assume that it shouldn't have any issues with the TR4 as well. The difference is about £300, so nearly 400 bucks. The RAM is just stupidly overpriced, I hope that the Samsung, Hynix and Micron will be fined heavily for what they've done.

 

[kanewolf]

If you choose to not use a matched set of 8 DIMMs I would recommend a minimum of 24 hours (maybe 48 hours because of the 128GB) of MEMTEST clean before releasing to client.

 

[feelinfroggy777]

Thank you guys. The QVL is often has to be updated, so I agree it's a lottery, I asked for advice as this is a new build for me and indeed there are a lot of complaints about the TR4 RAM compatibility. The KIT I'm on about is supported by the motherboard, but the one I want to get is for the Dual Channel only - so just 2 sticks and if I get 8 of them in theory it should work as it's supported by the motherboard and the CPU manufacturers. Also this RAM (Crucial) works perfectly fine on the 1800X CPU, so I would assume that it should've have any issues with the TR4 as well. The difference is about £300, so nearly 400 bucks. The RAM is just stupidly overpriced, I hope that the Samsung, Hynix and Micron will be fined heavily for what they've done.

Yeah, I don't even want to know how much 128gb of RAM cost. Yes, if you get 4 (2x16gb) kits and run all 8 sticks of RAM in the system it should work and will run in quad channel. But again, there is no guarantee so I would get it from a vendor who accepts returns and you should be fine.

 

[ITFT]

I always test all my PC builds for 3 days before selling them, a proper stress test for the whole lot, not just RAM.
Thank you everyone.

By the way the ECC server RAM 32Gb sticks about half price compared to 2x16Gb sticks for desktops. So it looks to me that what is happening with the RAM market is a massive bubble.

 

[Frederic Jeanbart]

I've mostly built systems filling eight memory slots with two kits of four memory sticks. I've never had any problem using two from the distinct two kits on the same channel. A couple of times it even resolved RAM issues. Although I didn't try to use 2 kits of 2xsticks with a quad channel memory controller from the mobo (the stick itself does not have built-in attributes of dual or quad multiplexing - it's a DDR. The mobo's memory controller on the other hand, either in single, dual or quad channel mode - depending on the way slots are populated -, controls the data passthrough from the memory slots, where the sticks are seated, to the later), I think that it should work as well. I've heard of no one having had an issue by using dual kits for a quad channel controller. As long as they're of the same model with same latency and timings, freq. etc., they would most probably work together.

Note : since dual channel kits would be absent from a quad channel mobo QVL, one approach is to look at the most mainstream memory stick that's in the list and that has the attributes you're looking for. Then verify a match with CAS and timings, + frequencies (base and OC/XMP, although that's not very impacting, it can even be the main reason of using dual channel kits for a quad channel memory controller). A look at the chipset could be relevant in finding a model from the QVL that also has it with similar features.

It's frequent to have two market versions of the same memory stick : dual channel kit, and quad channel kit. Depending on stocks and availability, sometimes one can be tempted in buying the dual channel version x2, instead of the quad channel kit, when the sticks themselves from both kits show that they'd be the exact same memory from the same manufacturing process (the quad kit being on the QVL). Apart from memory features and branding, this can be exposed by the model number itself, via slight differences - usually within the last digits.