Briefly explain how UEFI works, and why I need it

[blackangst1]

Ive been reading more and more about UEFI, and tried reading a few things about it, but I guess Im not getting it. My mobo supports it, but Im not using it. Would I benefit from it?

Here's my stuff:

Win 7 Ultimate 64 bit
MSI Z77 G43 mobo
Intel 4770k CPU
8 gig memory
Samsung Pro 850 OS drive
Seagate 1TB platter drive for storage
TPM chip on mobo for full disk encryption visa Bitlocker

I remember when I got the mobo one of the first things I did in the BIOS as I always do is take off any bootable media options I will never use. I remember seeing some UEFI options in the, but didnt know what it was.

So what say you?

 

[KingFatty]

I'm considering this option as well. From what I understand, you can't just change your BIOS settings from legacy BIOS mode to UEFI mode and expect it to work, because UEFI uses a different storage format and will try to find a storage device supporting the format, but all your boot drives will be in the older MBR format. So to get it to work, you'll have to reformat and reinstall Windows, only after changing the motherboard settings to UEFI. I think? Or maybe you can back up your old drive, then reformat to the new UEFI format, then reinstall (the format is GPT or something, I'm just calling it UEFI for simplicity).

Anyway, as for what benefit you'll see, is it should boot up slightly faster. There is a youtube video showing two identical older Dell laptops side-by-side performing simultaneous reboots, power ups, log outs, etc. One is UEFI and the other is legacy BIOS. The UEFI is slightly faster each time.

For drawbacks, I think you will need to access the motherboard settings using Windows instead of the mobo BIOS or something, not really sure if there are any significant drawbacks?

Maybe someone can elaborate or correct my assumptions. I plan to switch to UEFI when I next reformat/reinstall my computer, perhaps in a few months. But it's not a simple change of settings.

 

[Insert_Nickname]

Just to clear up a few things. UEFI is the BIOS. Or rather its a form of BIOS. You can think of UEFI as a much more capable version of a standard/legacy BIOS.

You can't change UEFI to legacy BIOS, but UEFI include (often, but not always) a BIOS interpreter for legacy compatibility. This tricks the OS into believing its dealing with a legacy BIOS. Which it of course isn't on a UEFI system.

So what you're changing is the installation mode of the OS. A newer OS* can (usually) be installed in both BIOS and UEFI modes. Some functions may require the UEFI mode to be used however.

I hope the above makes sense. Perhaps someone can explain it better.

*For Windows that's 7 and later. Technically Vista had UEFI support but only with SP2, but its a pain in the you-know-what to get working...

 

[ZimZum]

If your putting together a new sysytem sure go with UEFI. But if your talking about upgrading an existing bios to UEFI that just seems like way more trouble than its worth. My rule with Bios' is, if it aint broke dont fix it.

 

[Hi-Fi Man]

UEFI is part of the replacement for BIOS. UEFI isn't the firmware itself though, it's an interface for the actual firmware on the board.

UEFI removes many of the legacy limitations that BIOS imposed (such as not running in 16-bit real mode). It supports GPT partitions for boot disks (Windows in UEFI mode only supports GPT boot disks). It also supports a shell interface for performing advanced functions. It even allows drivers to be loaded.

Right now Windows and Mac OS X take advantage of EFI/UEFI the most. Windows with UEFI allows secure boot, GOP, logo replacement and reboot to UEFI. Newer Macs leverage driver support to download OS X onto a machine without an OS along with other recovery options.

To those who don't know, please don't refer to every firmware as a BIOS. BIOS was invented by IBM and reverse engineered by others to use on x86 PC compatibles.

If you want to switch to UEFI mode you will need to change your boot disk to GPT from MBR and create an ESP about 200MiB in size that is before all other partitions. There are various ways to do this but it can be quite involved so the easiest way is just to reinstall windows with UEFI enabled in the firmware.

 

[Puffnstuff]

UEFI provides a faster interface between the hardware and OS. If you want to use it then you have to set your bios to load it and reinstall windows in uefi mode.

 

[blackangst1]

Thanks guys.

 

[Joepublic2]

I have a similar machine and use windows disk encryption software that's incompatible with the windows UEFI boot process because it doesn't support booting off GPT partitions. My machine still boots in about 5-6 seconds off the SSD in BIOS compatibility mode, so unless you have a pressing need for a new feature UEFI provides I wouldn't worry about it.

 

[blackangst1]

I have a similar machine and use windows disk encryption software that's incompatible with the windows UEFI boot process because it doesn't support booting off GPT partitions. My machine still boots in about 5-6 seconds off the SSD in BIOS compatibility mode, so unless you have a pressing need for a new feature UEFI provides I wouldn't worry about it.

Yeah I dont think Im going to. If its not broken...