What?????! How did you manage to put non-emulated Win10 on Xserve 3,1? I've read all over the place that the bootrom doesn't have EFI support for windows hence the need for an emulator. I'd like to try this as well.
it was actually relatively simple in the fact that
despite what people say every intel mac can EFI boot windows but there is 1 thing, the older Mac EFI implantations lack some sort of EFI display protocol that the windows Boot loader uses so if you try and boot windows in EFI mode on those older macs it will look like the Boot picker has simply frozen
but what people dont know is the fact windows is still booting but just without any picture, so if you take a windows EFI install set it up enable screen sharing/remote desktop you can EFI boot windows on a lot of macs, including Xserve3,1 (I have also EFI booted windows 10 on a MP1,1-2,1 MB2,1 and MBP3,1 this way I have also Booted Windows 10 in EFI mode my Mid 2009 MB5,2 but that is one of the later macs that will work with the windows 10 boot loader properly and display a picture)
then what you can do is install a modern video card and then install the drivers for that card and boot blind and with any luck once the drivers kick in the connected monitor will light-up with the windows login screen exactly like booting OS X with a PC video card, I recommend pulling any Older NVIDIA Tesla architecture based EFI video card as the drivers for those dont play ball with Windows in EFI mode on any Mac. (in my above windows screen shot i had the GT 120 disabled in device manager)
this is one of the reasons I wanted to get an Xserve3,1 as i knew i should be able to do this and boot windows 10 (sadly windows 10 BSODs on my Xserve1,1 during the boot processes and I dont know what on as of course im booting without any picture effectively)
(the interesting this is for macs from about mid 2009 onwards apple updated the EFI so the protocol the windows 10 boot loader calls upon is there and on those macs you get a picture in windows before the display drivers kick in, im curious if the MP4,1 B08 and XS3,1 B09 firmwares incorporate those changes.)
speaking of Xserve I just finished upgrading the CPUs in mine using the Dual X5570s I pulled out of my MP4,1-5,1 when I upgraded that to Dual X5677s
(for those wondering 5GTs PCIe 2.0 is enabled by the NVIDIA drivers for the GT 740 Mojave was installed using @dosdude1 awesome utility )