One key difference is the Mortar MAX was, as all of MSI's MAX boards, built to handle Zen2 processors so BIOS support is assured right out of the box. Updating a Bazooka will require an earlier model CPU or APU to update the BIOS.
Also, while nothing's set in stone yet MSI will undoubtedly release BIOS to support Zen3 processors for their MAX boards. MSI pitched a fit when AMD first came out with non-support of Zen3 on B450 platforms because they the re-design of the MAX lineup was intended not only for Zen2 but to be ready for Zen3. It's not as likely they will release a Zen3 BIOS for non-MAX boards like the Bazooka though.
The Mortar's VRM is so good (for an AM4 mATX board) because it has two hi-side as well as two lo-side FET's, 4 FET's total for all (4+2) phases while the Bazooka has only one hi-side FET (not sure about the Bazooka Plus). That gives it the current/power handling of an 8 phase VRM, although it retains the voltage stability of a 4 phase. It also uses FET's that have fairly low RDS-on spec's so have good thermal performance under heavy load (not sure of the Bazooka). Couple that with the extremely large and well-finned heatsink and it's a cool-running VRM that easily supports 8 core CPU's -- even overclocked -- and remains comfortable up to a 3950X in a well ventilated case (un-overclocked). Probably the only B450 mATX motherboard that can be said for.
I have a B450m Mortar (non-max). And yes, it does have VDroop under load but so do all boards as that's the nature of it. The Mortar's LLC doesn't compensate it very well though when trying to overclock in the conventional fixed clock way which wants an extremely low, flat voltage. Also, the VRM measurement point is close to the VRM output but that's easy to work around since you're supposed to use SVI2/TFN voltage reading (reported by the CPU) anyway. Also, when overclocked using PBO Zen2 CPU's actually like VDroop since they need higher voltage to boost single cores at light loads (up to 1.5V by design) and then lower it under heavy all-core work loads (down to 1.275-1.325V). The secret I found to setting up my system was incorporate the motherboard's natural Vdroop into the CPU's own voltage control algorithm under load. That makes the LLC controls more meaningful.
Last edited by buddywh; 07-12-2020 at 06:13 AM.