I Have heard that AMD maybe doing so that why I need to know is AMD going to remove multi/gpu *(crossfire) gaming . I was thinking cos I already have RX 580 8GB and it sounds stupid to just buy new single card and let my RX 580 to get dust. Asking because I really would like to get some performance boost later this year. And I know that every game does not support crossfire but are they going to remove it slowly or trying to make it better if you can understand any of this ;D. And is there a problem with DX12 and crossfire?
With DirectX 12 and Vulkan support for multiple GPUs is built into the API, it has nothing to do with AMD nor nVidia, it is 100% on the developer. With DirectX 11 and earlier multiple GPU support was up to the developer to enable Crossfire and/or SLI support, then up to AMD and nVidia to develop Crossfire and SLI profiles for the game. So strictly speaking, Crossfire and SLI are nearly dead.
Heck slap another 580 in there you should see a nice difference - It will do 4 way if you have the slots. You can catch some sweet deals on Ebay with so many miners throwing in the towel over ASIC. Heck I just sold 4 570s some cheap. I game with 2 Vega 56 and like a lot no problems at all. Don't see it going away anytime soon. I hope.
I think there is some difference in the terminology there. Crossfire and SLI specifically refer to running multiple cards in DX11 applications and earlier. Multi GPU is the termed used for support in DX12 and Vulkan based applications. As has been already mentioned, and graphics card that is DX12 compliant will support MultiGPU, it is then up to the game developer to include support into their engine. So as long as the games you buy in the future support DX12 MultiGPU you should be fine. For DX11 titles, there will still need to be a crossfire profile supplied by AMD.
As more games go to DX12 and Vulkan, I think Crossfire profiles will disappear, but developers can still choose to enable MultiGPU support in their titles.