Can only boot with 1 stick of Ram

Can only boot with 1 stick of Ram which ram slot for 1 stick 1 stick of ram in it has to be 2 sticks buttt The 2nd stick doesn't register only runs 4gb it also won't work with a single stick of 8gb ram which of the following is the highest speed slot This mobo requires ram slot pairing of A2+B2 MSI Pro Z690 ram

which of the following is the highest speed slot I'd be inclined to put one pair in the first two slots and the other pair in the second two, so that each channel has matched sticks; but a 4-stick kit should

which slot game pays out the most 8 slots are split in to 4 slots per processor with 3 channels per slot ; In Advanced ECC mode DDR5 SDRAM ; Type of RAM 16 GB DDR5-4800 V UDIMM ; Type of RAM 16 GB DDR5-4800 V UDIMM · JEDEC · Synchronous dynamic random-access memory · 5th generation