[Solved] Screen-flashing bug with 5700 xt on Catalina beta (and Windows 10)
My primary monitor, a 3440x1440 Samsung S34E790C, will randomly turn black for a second or two, then turn back on. It seems as if it doesn't do it when I first turn everything on and starts after about 30 seconds or so, so I think it might have something to do with thermals. I never seem to see the fans spin. But my 1920x1080 TV, plugged into an HDMI port, has no such problem; it runs perfectly fine. But the ultrawide monitor flashes incessantly regardless of which DisplayPort output I connect it to. Does this sound like I have a faulty card? Or is it likely something with the beta drivers? Has anyone else had this issue? I should note that I used the exact same setup with the GPU swapped for a GTX 1070 until just a few days ago, and I ran all of that on Windows 10 just fine with no workarounds, so it's probably not anything other than either the MacOS drivers or the GPU itself. I would test this card on Windows 10 to be sure, but I've been struggling with Error 12 and am currently working through my third reinstall to try to get the right version. And obviously I could try swapping the card out but... I'd really rather do that as a last resort. Any ideas?
After finally getting the card to work on Windows, the problem persisted. So I realized it had to be some kind of hardware issue - but just to be sure before I went to go exchange the GPU, I asked one of my roommates for a displayport cable, and... it worked. I guess I must have damaged it while unplugging my eGPU. Mystery solved.
I was even able to turn my existing displayport cable around and it works.
Just FYI for anyone that happens to come across this page with the same build as me, this setup DOES work without any funky patches, you just need to downgrade Windows. For the 5700 XT to work on windows 10 as of right now, you need to be on windows 10 patch 1903, build 18362.295 (1. earlier builds may also work, but I couldn't get it to work on any patch 1809 builds. 2. the most recent release build at the time of this post is 18362.418 from oct 8 2019).
To get here, you have to download the iso for "Windows 10 1903 v1" as opposed to v2 (so you'll have to download the ISO from something like archive.org as Microsoft only offers 1903 v2 and 1809 right now), disable all updates, and then manually download and install KB4512508 (aka 18362.295) from the windows update database. After that, you can hotplug the eGPU any time after the windows logo shows up during boot and I'm set (you can plug it in as soon as it appears, if you don't want to wait).
Thanks for the details on how to achieve this. I'm going to use an eGPU with bootcamp for the first time, and this is really helpful. Would you mind sharing what precautions and steps you are taking so that you stay on build 18362.295 with no risk or worry of an auto update? Thanks.
I tried following your directions and grabbed a copy of 1903 v1 from the archive site you mentioned. However, it installed and it’s at 18362.30 right away. How were you able to downgrade to 295? Or did I find a bad/too updated copy that’s not a true V1? Not sure what I did wrong and am stuck. Thanks if you can give any advice I’d appreciate it.