I'm not real up to speed on these new self-built Motherboards, but on OEM Mobos using an SSD bootdrive only, I haven't seen any issues with enabling or disabling fastboot in BIOS. The SSD is so fast compared to the old mechanical HDD's, the BIOS barely gets time to be read before Windows starts it's HAL scan and bootup. On OEM computers, I didn't notice but a 1-2 second difference (if that) between having fastboot enabled or disabled in the BIOS. If you're the OCD type and you can pick up 2 seconds with having it enabled, then do so as long as it doesn't cause the BSODs. Of course, you won't know that until you bite the bullet and reinstall the v1703 CU update again on your existing hardware.
I think that kemical is on the money about you trying both the Update and Clean Install when you do try it. The Update is giving me fits, and I'm currently publishing an article in our local Computer Club newsletter about it. The latest word we have directly from Microsoft is that their servers now report 400 million computers have the v1703 Update with zero failures! Bahh! I have 3 out of 3 failures right here. The Update didn't install automatically, as reported by Microsoft said it should. All 3 had to get Updated via the new
W10 UPGRADE ASSISTANT tool. And 1 of them failed using the tool even after 5 times trying. This is just slightly better than any of the previous W10 build updates going all the way back to Sep. 2014 on the Tech Preview builds. My opinion is the same as kemical for these reasons, the v1703 CU Update is deeply flawed and we are telling you this to simplify the fixing of your problem--
SIMPLY DON'T USE IT!! Do the Clean Install as we are recommending. Period.
Then if the BSODs continue to occur, you can post your dump files so kemical and others can examine it and help you figure out what device or driver is causing the actual problem. Why complicate things by doing the Update which we already knows doesn't work correctly?
Best,
<<<BBJ>>>