You're sure the W7 ISO isn't jacked?
You have tried installing on a SATA drive rather than SSDs in a raid? (SSDs+raid=bad because of garbage collecting when I looked at it 6 months - a year ago... could be different by now)
You have put W7 on a jump drive with the Windows tool and tried to install from that?
Microsoft Store Online
It's strange that your computer is also going slow after the install. I would be leaning toward that hard drives here. I would unplug every HDD but one of the SATA drives. In fact, with everything you tried I would just put W7 on a jump drive, unplug everything but one stick of ram and one HDD and give that a shot.
After the HDD I would, like you, move to the MoBo. It most cases this would be extreme, but it would be my next move. Two weeks without PS2? Send back the mobo