MSI X299 TOMAHAWK AC Quick Start Manual page 28

Memory module installation recommendation (2-Channels architecture CPU )
B1
1 DIMM
2 DIMMs
3 DIMMs
4 DIMMs
DIMMB1, B2, A1 and A2 are un-available
18
Overview of Components
B2 A1 A2 Intel Core X-series CPU
Supports 2-channels
memory architecture
DIMMC1
DIMMD1
DIMMC1
DIMMC2
C2 C1 D2 D1
DIMMD1
DIMMC1
DIMMD1
DIMMD2
DIMMC1
DIMMC2