GB used to crash my system, too. I'm using iMP 1,1 with iGPU disabled. I'm also running Clover and Mojave. No Sleep, bluetooth, wifi, and other "fun" features are off. CPU is at 4.0 GHz AVX is at 0. Tonymac-oriented kexts are loaded from the EFI. SIP and Filevault are disabled. The RX580 is switched to "Compute" mode. –Obviously, this computer is in "dad-mode" for Pro Tools.
Is you PSU only 500W? I have an idea for you to try. It involves reducing your CPU and RAM clock a bit. You may be running the system too hard. Also, avoid bus-powering USB and TB stuff whenever you can until you can buy a higher capacity PSU. The PSU was the third thing I picked out when I designed my build. It's a Seasonic 1000W Titanium one. For my power draw, it's at its most efficient operation. I love that thing. It's totally silent. Okay, look at these images. My RAM is running at 2666MHz and I've clocked my i9 9900KS down to 4 GHz for the summer. My cores all sync, but IDK if yours will. I'm not a fan of running a machine flat-out just to push benchmarks higher. You could try a turbo setting of 4.5 across all cores. I had problems with the i9 9900KS at 3.8GHz, so 4.0 GHz it is –in my case.
Turn off XMP and set your RAM to 2666 MHz.
YMMY, AYR, etc. My CPU might require less juice because it's a binned one from SL. Again, YMMV. If you make these changes in BIOS, save them to a New File, don't overwrite your old one, and don't just hit "Save and Exit" –you'll need to differentiate between the two setups. FYI, the machine may restart a couple times before the BIOS screen reappears when your make changes to the RAM speed and/or CPU clock. Give everything a careful look. Good luck. LMK what happens.
@jb007 @pastrychef @CaseySJ