Grub option choice (nvme not detected)

After a bios update the nvme wasn’t detected, grub had smt=off but that wasn’t enough anymore, the new Bios changed more things which xen couldn’t handle yet.

Adding x2apic_phys=true made it boot up again.
I read here that dom0_max_vcpus=1 dom0_vcpus_pin should also work which i am going to check after posting this but now i wonder which is the better choice. From the looks of it the second one but how does one determine this for his chipset x570 and cpu R9 5950x ?

PS 4.1 qube, will check RC3 later this week

x2apic_phys=true works better and is booting up faster for this hardware case, while the other setting needed more time to boot and had problems with sys-usb mouse.
Speed difference makes sense since only 1vcpu is used to do all the dom0 work especially during boot and AppVM start ups.

Would have to run more tests with dom0_max_vcpus=2 dom0_vcpus_pin or 3/4 etc.