Mobo Ram Slots

Will it work as Dual Channel mode, if i use 2.4GB and 2.8GB ram stick in a motherboard which has 4 ram slots.? Mobo: Asrock b450m pro4 Pro: Ryzen 5 2400G.

Hi, I got this new mobo and 2 sticks of ram wont work in the first two slots. The ram is brand new from OCZ. I have 8gb of the same type of ram, and only the last two slots seem to work. When I put all 4 in or just first 2 the computer wont show a picture. I know 8gb prob is to much for just cod/mmo, but its brand new and it doesnt work.
Is there a program that I can use to test the slots? Or maybe Im doing something wrong?
Mobo: http://www.newegg.com/product/product.aspx?item=N82E16813131232
Ram: http://www.ocztechnology.com/produc..._6400_vista_performance_gold_4gb_dual_channel

Motherboard Ram Slots Not Working

Not all RAM chips can mix and match the memory slot of your motherboard. For example, if your motherboard was designed for DDR4 RAM, the memory slots of your motherboard cannot fit other types of RAMs like DDR3. Besides, the motherboard memory slots usually are integrated into the board and cannot be changed.
The RAM slots for many motherboards are limited to either two or four. In the latest upgrades of AMD motherboards, they were able to incorporate as many as eight RAM slots. With the help of these eight slots, one can expand their RAM capacity to 128GB. This ensures that the rest of the components reach their full potential.