Hello all!
I'm doing a Windows 8 PC repair for a friend who's hard drive died.I've installed a new drive,and have installed Windows 8.1 MCE and Office and the loader(KM Spico)antivirus,browser,extensions,updates,etc.

My question is, Is there something I need to do to make it run in UEFI mode? In the bios it's still set to Legacy mode because it had to be to read from DVD,but is there something that I do before I set it back to efi in the bios?

I'm not real experienced with windows 8,(Though I'm very experienced with windows in general)

Also if someone could explain to me the advantages of using UEFI vs legacy that would be very helpful.
I'm not certain but I think it deals with the bootloader. Does it protect your bootloader?

If I remember correct a few Hackintoshes I've done a few yrs ago used efi.
I also remember repairing a lot of Win Xp bootloaders with Hiren's that were corrupt or missing.Never had that issue on Win 7

Anyway,any input would be very much appreciated. Thanks in advance

 

http://www.uefi.org/faq

Mainly for HDD bigger than 2tb it's & faster boot times..also nice interface

 

Hmm, from what I remember reading, if you installed in in Legacy, you need to reinstall it all if you change it to UEFI. You can't just change it on the fly.

 

Im not an expert, but I did stay at a Holiday Inn last night.

I don't know exactly if it is ok, but I have turned UEFI on and off plenty of times. As far as I know it is just to run secure dvds and usb drives. Its like antivirus running. Only secure devices can be booted. I'm pretty sure windows has nothing to do with it. It is just security for bios and boot methods. I have win8 on an hp laptop. I disabled UEFI lots of times to be able to boot Hiren's boot usb. Then turned back on again. No issues for me.

 

if your system works it works. No speed advantages or anything.

If anything it will be harder for bootloaders to work in UEFI mode because there is more a 'direct link' between the UEFI and Windows boot process. Putting a loader into that chain will make the bootchain invalid in case of Secure Boot for example.

Mostly, if you need UEFI mode you need to install it _with_ UEFI mode (install from USB stick for example, but UEFI should be able to boot from DVD as well).
The same goes with your SATA setting to 'AHCI' or 'IDE Compatible'. If you install Windows in IDE mode, you can't change it afterwards (more speed from SSDs for example), it will bluescreen during boot.

Once again, if your system works as it should now and it's in AHCI mode there are no benefits from changing things. Maybe the > 2 TB harddisk thing, but I haven't seen it 'in the wild'. My 4 TB drives work fine... although they are supplied with a special driver in case your system has issues with it (mine didn't).

 

Legacy mode is intended (primarily) for windows 7, and any other previous OS other than windows 8. So I am presuming you just went gung ho with the install without looking any of this up, and thats ok, its easy to overlook. Everything about how windows is setup, from what you previously knew, is different with windows 8, and even moreso when dealing with UEFI - if you want to set it up right... and in Legacy mode, you didn't do it right (but not from a literal sense).

UEFI is also not an easy thing to learn, because while it is supposed to be "open" and extensible (only to proprietary developers), there is not a whole lot of information out there about it, even though its been around for several years. UEFI isn't going away, so you might as well take the time to read up about it in your free time.

Windows 8 is meant to have the UEFI parameters set to Secure Boot, it is what it was designed for, BUT it is not necessarily a requirement (you do not have to use secure boot). Secure boot helps to prevent unsigned drivers/programs and unauthorized operating systems from loading during boot, such as the propagation of malware into the bootsectors of the drive, etc, etc. To use legacy mode or secure boot, is really up to you.

Anyways, to get your installation media to boot into UEFI mode, when you put your x64 Windows 8 DVD installation media in the drive, press f9 for your boot options, select the dvd drive/windows installation media option with UEFI next to be able to boot the dvd windows installation media into UEFI mode (there will be 2 options, one is to boot the media without UEFI), and you can proceed as normal from there. However, you will probably need to delete all of the partitions you made, since they are more than likely MBR instead of GPT, since you installed it without UEFI mode.


Some info about uefi and windows 8 courtesy of eightforums.com:
http://www.eightforums.com/tutorials/29504-bios-mode-see-if-windows-boot-uefi-legacy-mode.html
http://www.eightforums.com/tutorials/17058-secure-boot-enable-disable-uefi.html
http://www.eightforums.com/tutorials/20208-secure-boot-confirm-enabled-disabled-windows-8-a.html
http://www.eightforums.com/tutorials/2328-uefi-unified-extensible-firmware-interface-install-windows-8-a.html
http://www.eightforums.com/tutorials/20256-uefi-firmware-settings-boot-inside-windows-8-a.html

Hope this helps a bit! )

 

The three main advantages of UEFI are

• Secure Boot (not sure if really an advantage...)
• ability to boot HDDs > 2 TB
• some nice features for multi-booting

You can not change from Bios to UEFI after you installed Windows, since the disk needs to be partitioned with GPT instead of MBR.

 

Awesome info! Thanks guys this is exactly what I needed to know.

 

In case you need to install bootable windows 7 in >2tb disk you need to re-burn the dvd/usb drive into a special UEFI, and make proper partitions in order to work (i managed to do it on an ASUS G73jh)

 

Faster bootup times are also a feature of UEFI and you can have it on or off. It checks if a loader is signed and on a whitelist before execution. Unfortunately it's not completely secure. I read an article just recently about A new way to bypass Secure Boot security mechanism of UEFI but that's another story.