Question Quad Memory bandwidth on TRX40 chipsets

[exonian]

I just built the following kit:

• CPU: AMD Ryzen Threadripper 3960X
• Motherboard: Asus ROG Zenith II Extreme
• Memory: G.Skill F4–3600C16Q-64GTZRC (CAS 16 i.e. CAS to Freq Ratio: 0.44 — with estimated latency of 8.89 nanoseconds)
• HDD: 2 x Samsung 980 PRO NVMe on RAID 0

Although this is supposed to be a quad channel configuration (4x16GB sticks) that should provide a memory bandwidth of around 100GB/s, the measured bandwidth of my memory is around 40GB/s - as if it is a dual channel.

I have setup my sticks as indicated by Asus, i.e. in A1, B1, C1, D1 slots.

Yet, I just came across this video that suggests that in order to get the quad channel performance you should put them in A2B2C2D2 slots.

Obviously it for another ASUS motherboard but I am just wondering if ASUS have made a mess of their manual on ROG Zenith II Extreme and that I should try moving to #2 slots from #1.

Has anyone here noticed this issue?

If this is not the issue, then why the bandwidth is so low?

Last but not least, with my memory, I was expecting to get a very decent latency, yet my scores are awful.

I have uploaded some screenshots here

I have set my memory setting in the BIOS to auto (other than choosing the frequency to 3600).

Should I add the setting manually?

Thank you for your help.

 

[exonian]

Just to let you know that it runs as quad in ABCD1 and that the aggregate throughput/bandwidth is over 80GB/s.