Bootable Windows 8 UEFI USB?

Okay I am a bit lost in your post last statement as compared to the rest. UEFI replaces BIOS as a software enabling boot system that relies on the Boot OS drive for what BIOS used to do. As far as I am aware, you cannot in anyway make a 'bootable' Windows on a Ext USB, especially for UEFI as it is looking 'internally' for the Boot OS to fulfill the BIOS role. As far as UEFI is concerned "USB .... uhmm what do those letters mean?" because it hasn't the 'brains' or knowledge to know the difference of USB to Mouse to Parallel Port to anything else, it then (as programmed) seeks out the Boot OS with the information it gathered and let the Boot OS know what hardware codes it found for the Boot OS to them implement the Drivers to access and talk to the hardware at the application layer as compared to the much lower physical layer (think 7 layer model OSI modelling http://en.wikipedia.org/wiki/OSI_model).

Now GPT partitioning is for the newer 4K drives, that is the drives are segmented into 4K bits to increase the 'storage size' on the same space the old 512k bits space was used on older drives. This is a manufacturing specification and how the 'drive' is built, internally or externally doesn't matter. So if had 520k of code to store, I don't "waste" 1M bits of two 512k segments (512k+512k makes 1024k) but instead use 130 "4K segments" and thus more 'space' on the same physical platter is still available for use.

Now your last statement really makes no sense as none of this will lead to faster BIOS boot time, and the Windows Fast Boot was meant for the very low end netbooks that were sold with Vista that didn't have enough RAM to begin with to 'boot' the OS (which the Windows Fast Boot is for booting the OS not the UEFI nor BIOS) when using a external USB RAM as a Boot RAM drive as your trying. SINCE Windows 7 and now into Windows 8, Windows Fast Boot denotes the method in programming and organization that Windows has built in to 'delay' some start up elements in the most 'optimal way' so you "get to the desktop" as quickly as possible. This does NOT mean stuff 'works' it just means you see the desktop and icons and can move the mouse around. But again this a OS (application) layer NOT physical layer implementation.

Your only way to 'drastically' improve, other then having literally NOTHING 'start up' when you turn on Windows, is to get a SSD. All these tricks are limited to the hardware (physical platter head reader speeds - mechanical drive limitations) and would only get enough of a 'fast' boot (the infamous 7 second boot) with SSD. The best you can do (clean totally nothing installed Windows) is around 12-15 sec of 'turning on' Windows on a 7200RPM drive, but you can't "do" anything realistically / leave your system completely vulnerable.

Ahem.... the link I provided http://pcsupport.about.com/od/windows-8/a/install-windows-8-usb.htm from my simple google search if you follow the directions QUOTE:

Step 12: Boot from the USB device ...

Tip: If you have a UEFI based system and you still can't boot Windows 8 Setup from the flash drive, even after setting the USB device first in the boot order, see Tip #1 below for help.

.... The Windows 7 USB DVD Download Tool formats the USB drive as NTFS, a file system that many UEFI based computers will not boot from when on a USB drive.

To work around this issue, do this:

After Step 11 above, copy all of the files from the flash drive to a folder on your PC.
Format the flash drive manually, using the older FAT32 file system.
Copy all of the files from the folder you made in Step 1 back to the flash drive.
Repeat Step 12 above.
There is an alternative method for getting a Windows 8 or 8.1 ISO image properly onto a USB drive. See How to Burn an ISO File to USB for a walkthrough. I prefer the procedure I've outlined above, but if you have trouble with it, that general ISO-to-USB procedure should work as well.

So my wife has a Amazon Fire, and like the VERY feature your cell phone and her Fire does, it goes into a 'hybrid' hibernation mode when you hit the 'power button', it doesn't actually 'turn off'. So when you tap the screen POOF it is all 'loaded' instantly, Windows 8 was designed to mimic this specifically for the 'tablets' it was to be sold on (screw us Desktop people is the unintended message they were really saying).

Note this is not COLD BOOT, this is (as noted in the article) putting your computer into a pseudo SLEEPING mode you're just instantly waking up from. If you power off your computer THIS will NOT speed up your 'boot load' as you previously indicated was the goal.

So I have in front of me a Lenovo Thinkpad 2, lovely tablet that runs FULL Windows 8 (not RT) that does this very feature you want. The new 'thin' laptops you see at CostCo, BestBuy, also have this same feature enabled and perform real well, advertising the 8 hours battery time or such (we are all used to laptops not even making it to the end of Lord of the Rings before needing a power plug!). These are based on two things you need to consider

1) Minimizing power consumption to the lowest level a User can 'deal with' (i.e. throttling your CPU to very slow, turning off Bluetooth, only using IG and turning 'off' the dedicated GPU, etc.)
2) Hibernation - hybrid mode.

F your Alienware M17X R4, this is NOT practical, as the hardware chews up battery life and can't be effectively throttled enough to mimic my Thinkpad 2, Kindle Fire, thin laptops being sold. So while you may try to implement this mode, most likely it won't be as 'effective' (as your article states "Milage MAY vary") as the OS / UEFI detects the power drainage and either turns things 'off' screwing up what you had 'open' or will just SHUT DOWN, saving your open apps in the normal Hibernation mode and you have a MUCH LONGER boot load time waiting for Windows to read everything in the Hiber.sys file stored with what windows were open, where icons were, etc.

Now I would warn you that I did a quick google on your model and Windows 8.1 https://www.google.com/search?num=50&newwindow=1&safe=off&q=alienware+m17x+r4+windows+8.1&oq=Alienware+M17X+R4+Windows+&gs_l=serp.3.1.0l2j0i22i30l8.23620.24808.0.27774.9.4.0.5.5.0.109.361.3j1.4.0....0...1c.1.51.serp..0.9.390.rOtSCKXPYFg

There is QUITE a few articles, especially issues the USB 3.0 has issues. First and foremost they all recommend doing the BIOS / UEFI update, then proceed on from there. I would recommend this site http://forum.notebookreview.com/alienware-17-m17x/749043-m17x-r4-windows-8-1-usb-3-0-a.html as they have a active community specific to your model (as they had one for us old R2 owners) that you can peruse through to find and resolve the issues you WILL encounter.

The best 'solution' seems to be those whom originally ordered the R4 with Windows 8, and use the recovery method to install Windows 8. Everyone else with the Windows 7 R4s have a bunch of hiccups and hoops to deal with.