[SOLVED] A question about RAM dual channels

[sinshock555]

So I'm using a pretty old PC running an MSI Tomahawk B350 motherboard, which has 4 slots of RAM labeled A1, A2, A3, A4.
Unfortunately, the A4 slot is dead, so I'm putting my 2x8Gb of RAM in the A1 and A3 slot for Dual channel. But when I turn on the PC I received a notice saying that my memory are not in the optimized slots (which are A2 and A4).
So what I want to ask is, that will my performence drop if I use the A1 and A3 slot because they are not optimized, even though they're both dual channels ?

 

[sizzling]

Download CPU-Z and check the memory tab, the channel should show as dual.