I just bought:
4x8GB Corsair Vengeance LPX 3000Mhz
ASRock Z390 Phantom SLI/AC mobo
850w Corsair PSU
WD Blue SSD 1TB
Display is a 55" TCL 4k TV #55R615. I had the same freezing and stuttering problem I've seen others struggle with, but I narrowed in down to 3 things.
1) Don't update your driver or download the game ready drivers. Use the one that came with the card, or try 431.6. Then set to application controlled PhysX, no scaling and 60 Mhz refresh rate. Also turned off sound through HDMI/Display and turned on HDR setting in Windows 10.
2) Uninstall GPU Tweak 2 and use Afterburner instead!! GPU Tweak was interfering with my CPU. I posted 700 marks on XTU with GPU Tweak 2 and 3250 marks immediately after uninstalling! However it didn't hurt my TimeSpy score, which is odd; but when playing actual games it seemed to be interfering.
3) Not sure if this was part of the issue, but it definitely helped. I Overclocked and tweaked my BIOS and XTU settings, which I will post pictures of. It seemed my CPU was taking too long to boost and didn't have enough juice to core or RAM.
Here is my Time Spy score, #1 for Geforce RTX 2070, #5 for single GPU...
And here are my XTU and Afterburner settings.
Note that the videocard is already OC'd out of the box, so you won't get much extra boost. +120 GPU and +400 Mem was the most stable for me. Benchmarked my CPU at 5.1Ghz, but I run it at 5.0 Ghz.
In my BIOS/UEFI I set CPU Ratio to All Core - 36 (100Mhz BCLK) , FCLK 800Mhz, AVX Auto, Short & Long Power Duration Limit to 4095, CPU Load Line to lowest setting, Core voltage auto, DRAM voltage 1.4. Rest of tweaks done in XTU. I'm no expert at all this, so any tips are welcome.