You should disable this BIOS option, because your system is obviously not able to run in "clean" UEFI mode (CSM disabled).
Hey guys,
I hope you all had a nice Valentine’s day / weekend.
Anyways, got back an hour or so and tried to install Windows 8.1 again… This time in Legacy mode, as explained above. Anyways; same crap again. Windows stops during the first part (copying files) or 2nd part at a random percentage (getting files ready). So the same as before.
Tried a few other things, same result. One really weird thing I noticed was when Windows installation got stuck at a certain percentage, my RAID array had 0 bytes free. No clue why or how that happened anyways, did a few Google searches and found some dude who was experiencing something silimar.
I read through his blog post and saw that he enabled the SATA hotplug option on all SATA ports. Sounds stupid, but anyways, I did that also, since I don’t have any other ideas left. And guess what… Windows just installed without any issue or hiccup… 
Now, I know I am not an expert and all, but does that make any, I repeat ANY, sense at all? Never heard of this before.
Since it installed, I am gonna retry again. Doubt it was just luck given the many times already I tried to install this crap (pardon my French).
I think it’s total BS though. Why would I be able to install Windows 8.1 without issues by enabled that hotswap option on the sata ports?
Fernando, you have a clue why this is?
As I said; I will retry this again and see what happens. It should install again; if not, it was probably just luck and wouldn’t have been stable anyways, I guess…
No, not really.
I made a typoe in my previous post; it’s called SATA Hot Plug, but I guess it’s the same as Hot Swap probably.
Anyways, removed the old array. Set BIOS back to defaults, reconfigured everything and setup an UEFI RAID 0 array.
Enabled SATA Hot Plug again on all ports and installed Windows 8.1 again.
Guess what…?
Again, no problems at all… Windows 8.1 installed without issues at all (also used a different stick with different Windows 8.1 on it; with all updates so far).
Really, really lame and stupid.
I was really close at throwing the towel in the ring.
SATA Hot Plug is one of the main benefits of AHCI, meaning the capability to remove drives while the system is running. If you try to do that in IDE mode/drives the system will most probably freeze or reset. Why it’s not enabled by default or why Windows doesn’t install without it, I don’t know. Maybe it’s chipset, BIOS, OEM specific. But since you found what BIOS issue was causing the problem, you don’t have to worry about it. It’s nice to have Hot Plug capability either way.
Yeah, I know what it means and/or does, but that’s why it didn’t make sense to me to enable it earlier. Never used it before either. So that’s why I considerate it strange.
By the way, I found that page which made me enable it, here.
Quote from that page:
Well I am happy I finally figured it out and how I finally could install Windows, but still wasted more than 3 days on this.
Maybe it’s bad luck with my motherboards, the two SSD’s and running them RAID. Oh well…
Thanks anyways for your help guys. 
@ HHawk:
It is fine, that you found out at least the origin of all your problems and were able to get Win8.1 properly installed onto your freshly created RAID0 array.
By the way: I have very often created an Intel RAID0 arrays and installed Win8.1 onto it without having enabled the “Hot Plug” feature for the related SATA ports, but never ran into troubles like you.
Since your problem has been solved I will customize the thrad title.
Enjoy the new system and don’t think too much about the frustrating last days!
Regards
Dieter (alias Fernando)
I’m just going to post a link because I don’t want to type it twice:
http://www.reddit.com/r/pcmasterrace/com…d_raid_0_fixed/
Keep motherboard set up for ACHI and create a Striped Volume and format in Windows before running installer.