Secondly, the first question, because AMD's graphics card has a firefight, it can only be selected in AMD's GPU. AMD's graphics cards have two kinds of crossfire. The first is the crossfire between discrete graphics cards, but the discrete graphics cards must be of the same model, otherwise they cannot be interchanged. The second is the crossfire between AMD's integrated graphics card and discrete graphics card. However, not all AMD integrated graphics cards have crossfire function, only the integrated graphics cards in APU can have crossfire function with discrete graphics cards. Moreover, this crossfire situation is concentrated between the integrated graphics card and the mid-range or low-end discrete graphics card. AMD's mid-to-high-end or high-end graphics cards do not have the function of fighting integrated graphics cards (but discrete graphics cards are still possible).
Finally, AMD's firewire crossing technology is far from mature at present. The improvement of graphics card performance by crossfire technology is not obvious. Therefore, at this stage, AMD's shooting technology, gimmicks are greater than the actual meaning, advertisements are more meaningful, and the practical value is not high.
Finally, just because your motherboard has three PIC-E slots doesn't mean it can support three graphics cards. Graphics card crossfire definitely needs high-power power supply, such as 600W power supply, which is the lowest, and 700W power supply is not unusual.