since one day now and with a lot of known issues ( therefore its a beta within the beta ) 
Comparing of DCS code-base and MSFS code-base is like compare apples with nuts.
Also, as DCS developers wrote: if you former was GPU limited, you are still also with the new multithread-implementatin in DCS GPU limited. Thats similar in MSFS. The MSFS developers work also on optimzations, hopefully. The stepwise switch to DX12, which is mainly same as Vulcan ( a low level api ) , is a part of that. Implement fundamendal changes in multithreading is just a dangerous step, like we see in DCS where some parts currently not works ( eg. known the garmin ) or stutters can occur now.