Help, PCIe Timer Timeout, and a Freezing Issue

[CatsPajamas]

Please I seriously need help... I'm not a total noob but this is baffling everyone.

(https://pcpartpicker.com/list/VHQ229)
CPU: Ryzen 2600x
Motherboard: was Gigabyte Auora x470 gaming 5 wifi, now Asrock x470 Taichi
RAM: Corsair Dominator Plantinum ddr4 3000mhz (2x8gb)
GPU: MSI GTX 1060 6gb
PSU: Seasonic 550w Gold+
samsung ssd, western digital hdd.

It worked for a day. Then started freezing. Then the SSD died (unrelated).

So I replaced the ssd and its still freezing... I was told to look at RAM, so tested 1 at a time and different configurations, still freezing. Passed memtest86+ flying colors, Its not the RAM. The first motherboard was rated bad, so I replaced that, still does the exact same thing.

I will go into details about the freezing: It only happens on GUI screens, not bios, not console based text programs, just windows and linux. I can leave it on the first windows installer screen all night and it wont freeze, but after a few minutes of moving windows around minimize maximize (the installer dialog), it freezes.

I ran a CPU stress test (prime28.5 off ulitmate boot cd) and PCIe timer timeout errors pop up every 10-30 minutes... I googled and couldn't find anything. But that suggests graphics card? I've ran a VRAM test and it passed it.

I have an RMA number for the CPU so will be remailing it, but it basically does work, its this freezing thing, think they will find it in there testing? what does this sound like to you?