Yes I have applied 3200MHz XMP profile to the 64GB RAM in the MSI Tomahawk BIOS.
It was that simple.
No Ryzen Ram Calculator or RAM Timing tweaking or multiple BIOS trials or ASUS or Corsair Customer support calls or large amounts of wasted time like on Maximus build.
I just plugged in the 4 16GB sticks and it booted up fine and I ran MemTest86.
This is what should have happened on the Maximus Ryzen 2700X build.
It should just work properly when the RAM is plugged into the motherboard.
I am thinking of selling the Ryzen 2700X on Maximus and replacing it with a Ryzen 3000 series CPU now.
I will have to prove that it is the CPU that makes the difference and it is not the ASUS motherboard that is the problem though.
I think that Ryzen 1000 and 2000 series CPU do have poor Memory Controller performance versus Ryzen 3000.
OK I looked at the board - it looks good: B450 TOMAHAWK MAX | Motherboard | MSI Global
The specs seem very similar.
I think it is ~ same as the B450 Tomahawk but has a few additional features and comes pre-loaded with Ryzen 3000 compatible BIOS.
I note it has spec support for higher DDR4 memory frequencies.
It looks like a good motherboard and if it is anything like the B450 Tomahawk and the price is ~ same I would consider it.
If I were you I would look for product reviews of the board first though.
The MemTest86 results on Libertas with 64GB (4x16GB) Corsair Vengeance RGB Pro 3200 DDR4 in Memtest86 at 3200 MHz are OK. I stopped testing any further for now.
I swapped the RAM between Libertas and Maximus again back to the original state.
I will swap the RAM between machines again in ~ 2 weeks and do more extensive MemTest86 and Karhu Ram Test in Windows on both machines.
I need both machines running for the next two weeks starting today.
The Corsair Vengeance LPX 16 GB (2 x 8 GB) DDR4-3200 Memory would only run at 2333MHz rather than the spec 3200MHz for the motherboard and RAM when fitted in the Maximus build.
Note the BIOS settings and RAM timings on Maximus were those I use on that machine to allow the Ryzen 2700X to run at 4.3GHz and the 64GB Corsair Vengeance Pro memory to run at 3200 MHz with the ASUS 2901 BIOS.
Maximus PC would not even boot if I increased the RAM Speed in BIOS any higher than 2133MHz.
I would need to use the Ryzen Ram Calculator again for the Corsair Vengeance LPX 16 GB (2 x 8 GB) DDR4-3200 and probably get into another round of multiple Ram Timing Tweaks and MEMTEST86 runs. I do not have time to do that at the moment. It can take a very long time to tweak and verify the RAM Timings are ok for a particular BIOS.
I just decided to upgrade the BIOS on Maximus to the following ASUS BIOS:
ROG CROSSHAIR VII HERO(WI-FI) BIOS 3004
1. Update AM4 combo PI 126.96.36.199 patch B
2. Fixed a compatibility issue with M.2s when using Ryzen 3000 CPUs.
Before running the USB BIOS Flashback tool, please rename the BIOS file (*.CAP) using BIOSRenamer."
I have also decided that it is time to run backups and do a completely fresh reinstallation of Windows 10 Pro on Maximus.