Hi All, In my machine, Mac Pro 5.1 2010, with RX 580, the BruceX test in High Sierra 10.13.2 ran at around 20 sec. Now the same test under 10.13.3 runs at 32 sec. This is 50% lower than before. I think this was due to the Meltdown/ Spectre patch in 10.3.3. Tested in beta 10.13.4 is the same lower result. My FCP is 10.4. Can Any one confirm this?