PCIe SSD Showing as External Drive?

No.

Actually there is a way to fix this, I also got irritated by my own SSD showing the orange external drive icon. You need to install a free third-party kernel extension, it tricks OS X in to treating PCIe SATA drives and PCIe SSD drives as if they were internal drives. Apart from fixing the icon it also hides the eject option from the sidebar.

It does appear however you need to enable running unsigned kernel extensions for this to work. I have not re-tested this under El Capitan but it does work in Yosemite.

See http://forums.macrumors.com/threads/sata-pci-card-drives-show-as-external.188086 4/

I have not tried installing Boot Camp on my main SSD drive. (Which is a genuine Apple 1TB SSD on a PCIe adapter.)

I use a standard SATA drive for my Boot Camp drive however I did encounter something on that front which might give you a clue. If you use the standard built-in drive bays then of course Boot Camp will work fine, I however as part of my project to upgrade a Mac Pro 5,1 2010 model have 'converted' my internal drive bays from the original SATA II, to SATA III. I did this by getting a PCIe SATA III card with a miniSAS to four SATA connectors cable, and also getting a kit to replace the drive bay sleds with special ones that bypass the normal drive bay SATA connectors. This allows connecting the sleds to the SATA III PCIe card. For OS X nothing special has to be done it just boots, however for Windows via Boot Camp it would not initially boot successfully. This is because Windows did not have a suitable driver for this SATA card already installed. I was however able to install this driver while using the normal SATA II drive bay sled and then swap it over to the special drive bay sled and now it will successfully boot via the SATA III PCIe card.

If you are just using standard spinning hard disks then upgrading to SATA III like I did will make little or no difference but it does make a difference for SATA SSD drives. I did this more 'because I could' and I got the special drive sleds and cable secondhand off eBay.

So if there was a special Windows driver for whatever PCIe adapter your using that might help if you could pre-install it in to Windows.

My Mac Pro has had its CPUs upgraded to 2 x 3.06GHz which as a beneficial side effect also upgrades the memory speed and the Processor Interconnect speed making it exactly the same as a 2012 model, I have also upgrade the WiFi internally to 802.11ac and Bluetooth to 4.0 LE with both now fully Continuity/HandOff compatible, as mentioned the drive bays are now SATA III, I have a super-fast Apple SSD 1TB boot drive, and I have upgraded the video card to a Radeon HD 7950 which is Metal & 4K compatible. I am next considering a USB 3.1 card (yes it is possible to add USB 3.1).