Okay, so I recently purchased a 2010 Mac Pro after researching them for about 9 months, and was excited to have a speedy machine after my 2011 iMac's video card took another crap. I bought a fairly maxed out tower off of ebay, it arrived working great, but after about 2 weeks it took a crap in the middle of doing a photoshop action. The machine still booted off of the 2.5 with windows on it, so I figured it was the ssd with mac os on it. After reading quite a bit, I acquired an SM951 AHCI and pcie adapter. The seller said he'd installed High Sierra like I asked, but when I installed it I got nothing. I found it using target disk mode with my old MBP, and noticed it had a time machine back up file, with 2 folders... so I copied them over to my MBP, and then installed and booted successfully from Sierra (had it on USB already), but when trying to then install High Sierra, it wouldn't let me choose the drive as it said it didn't have the right firmware. I cantc really find much on making this work, so any help is greatly appreciated. Also, what OS and drivers do I need to run my flashed Titan X (maxwell)? I have a stock gt120 in it to reformat and install OSX. Thanks in advance!!