When installing Windows 7 Pro 64, I loaded in the raid drivers from the motherboard disk and installed Windows. I noticed that the install took a very long time, about 50 minutes. Upon bootingIe found boot times of 3+ minutes.
I have 2 WD Red 1TB drives with 64MB Cache setup in RAID1 on the motherboard. Motherboard is Gigabyte F2A88XM-D3HP Rev 1., CPU A10-6800K, Discrete Graphics R7-250X, 8GB memory (2x 4GB 1866Mhz)
I spoke with GigaByte, they had me try a number of things. The only thing that made a difference is dropping the RAID and reverting to IDE mode. Then boot time went to 23 Seconds. GigaByte says that based on that the problem is within either the driver from AMD or the chipset itself.
I verified that we had the latest BIOS from GigaByte, F2. Driver on the controller within Windows shows 188.8.131.52.
Running boot diagnostics also points to the driver being the problem.