i just finished installing my xp941 for the second time as a boot drive with win 7 x64 on that very board- it's not fun
here's a link to an instruction set using the latest BIOS (2701)
https://vip.asus.com/forum/view.aspx?id=20130111005429811&board_id=1&model=P8Z77-V+LX&page=1&SLanguage=en-us and a link to a thread that fed into the above thread
https://vip.asus.com/forum/view.aspx?id=20150408005817455&board_id=1&model=Z97M-PLUS&page=1&SLanguage=en-us
that link is to the latest instruction set - the combo of bios settings has evolved as bios updates have released
couple of tips, 1) make sure no other drives are connected to the computer
2) use
RUFUS to copy your windows 7 disk to create a bootable ISO image on a USB drive, formatted to FAT32
3) get a copy of the intel F6 AHCI/Raid driver and install it when you're installing windows - ie just before you start the install, after the language selection, there'll be an option to "load drivers" - hit that and load that Intel F6 driver first
The instructions on the web are all over the map - and while the above worked for me the first time, by accident, it wouldn't a second time - ended up using a "fred flintstone" backdoor method that got it installed
if the above link'd instructions don't work, post back in this thread, and i'll post my last instruction set
something else you might want to consider - installing that xp941 in the M.2 socket: 1) it kills sata ports 5 & 6 - asus euphemistically sez the "m.2 socket shares bandwidth with sat 5 & 6" - what they don't say and should is that when the M.2 socket is occupied, sata 5 & 6 are dis-abled, so you're gaining one drive port and loosing two.
2nd item - that socket is only two lanes PCIe
I ended up taking my M.2 xp941 out and ordered in an Addonic PCIe M.2 adaptor expansion card off amazon
http://www.amazon.com/gp/product/B00KDM75XK/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1
two benefits, mounted in the last or 4th PCIe slot, you've got 4 lanes PCIe, and 2nd you gain back those two sata ports
in the M.2 socket, my xp941 gave me 770 MB/s read, and 560 MB/s write. In the Addonics card in the 4th PCIe slot, i'm seeing 1203 MB/s read, 835 MB/s write. Big difference
boot times from the time i hit the power on button, 12-13 seconds, 5 seconds after the POST screen disappears