Are two identical sets of DDR4 (2комплекта memory 2х8Гб) in four channel mode?

Good afternoon.

I would like to know the opinion of experts on some issues regarding the choice of RAM, as well as about her work in Quad-channel mode.

Motherboard:

X299 MSI SLI Plussupports Quad-channel mode.

RAM (for example):

Corsair CMK16GX4M2B3200C16 (3200Гц, CL 16, 2x8Gb)6010₽
Corsair CMK16GX4M2Z3200C16 (3200Гц, CL 16, 2x8Gb)5350₽
Corsair CMK32GX4M4Z3200C16 (3200Гц, CL 16, 4x8Gb)sold out, presumably 19000-23000₽

Main question: is it worth buying a set of four laths on 8Gb or you can purchase two identical sets, each of which will have two straps with 8Gb (it is much cheaper) — will it work in Quad channel mode? If not, how significant the increase is the use of four-channel mode vs dual channel?

Because socket2066 implies a restriction of DDR4-2666, as I understand it, any memory frequency above 2666Гц will work on this frequency?

I will be grateful if I could clarify the difference between the two absolutely identical models of memory 2x8Gb above: CMK16GX4M2B3200C16 and CMK16GX4M2Z3200C16. From what I could find online, and letter "Z" only indicates that the memory was released later, apparently in connection with this it is cheaper?

Thanks in advance for your answers.
April 4th 20 at 13:19
2 answers
April 4th 20 at 13:21
CMK16GX4M2B3200C16
Memory Configuration: Dual / Quad Channel
SPD Latency: 15-15-15-36
SPD Speed: 2133MHz
Compatibility: Intel 100 Series,Intel Series 200,Intel 300 Series,X299 Intel,AMD 300 Series,400 Series, AMD,AMD X570

CMK16GX4M2Z3200C16
Memory Configuration: Dual / Quad Channel
SPD Latency: 16-18-18-35
SPD Speed: 2666MHz
Compatibility: Intel 100 Series,Intel Series 200,Intel 300 Series,AMD 300 Series,400 Series, AMD,AMD X570
That is, if the manufacturer's website says about the support of Quad Channel (even if the set of two straps), the purchase of two kits will work in Quad channel mode, right? - eunice87 commented on April 4th 20 at 13:24
@judy.Brown, Theoretically it should work. - Isabelle_Feest56 commented on April 4th 20 at 13:27
April 4th 20 at 13:23
Take though different kits, the main thing is to keep the 4 channel, and was one and the same frequency, voltage and timings. At least 4 different dies on the performance and stability is not affected.

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