Legacy rom vs EFI compatible rom

[Och]

I updated to the latest BIOS on my P8P67 Pro, and it now has this new option. Right now I have it set to Legacy ROM, haven't tried EFI compatible b/c I don't want to screw anything up. What the difference between them?

BTW, this board has one of these fancy new BIOS systems, where I can use the mouse and it has pretty graphics. I thought that is EFI?

[caveman-jim]

I updated to the latest BIOS on my P8P67 Pro, and it now has this new option. Right now I have it set to Legacy ROM, haven't tried EFI compatible b/c I don't want to screw anything up. What the difference between them?

BTW, this board has one of these fancy new BIOS systems, where I can use the mouse and it has pretty graphics. I thought that is EFI?

It is, now you have the option to EFI boot, like from GPT disks or run your hardware in EFI mode. It's cool. You want it

[FiggyG]

It is, now you have the option to EFI boot, like from GPT disks or run your hardware in EFI mode. It's cool. You want it

Any particular reason why? (Other than being able to use 2TB+ drives with 1 partition)

[0091/2]

Sightly faster boot up time?

[mabran]

Sightly faster boot up time?

On the first system in my sig, The difference between EFI boot and regular boot is about 1.5 seconds (hardly worth it for that alone) When I blink and my login is shown, it is fast.

I like EFI boot though and the GPT part is about the best reason to use it IMO

[Shadowless]

EFI boot rules.

[Kain]

I just noticed that I am on Legacy ROM. If I want to switch to EFI Compatible ROM, do I have to reformat? I've been told I will have to reformat.

[mabran]

I just noticed that I am on Legacy ROM. If I want to switch to EFI Compatible ROM, do I have to reformat? I've been told I will have to reformat.

There are ways not too have to but are too time consuming to make it worth it and too many areas to screw up. It easier to back up the data and reinstall.

[Kain]

In the BIOS, the setting is named "PCI ROM Priority". Doesn't this have to do something with PCI?

[Kain]

In the BIOS, the setting is named "PCI ROM Priority". Doesn't this have to do something with PCI?

Bump!

[Kain]

In the BIOS, the setting is named "PCI ROM Priority". Doesn't this have to do something with PCI?

Bump!

HALP!

[mabran]

HALP!

I would guess that is for legacy BIOS (i.e storage contollers, network etc with boot roms)

[caveman-jim]

If you want EFI mode then set PCI ROM Priority to EFI Compatible. This will initialize devices that are able to run under EFI first, like SSD/HDD/USB formatted with EFI partitions, EFI ROM video cards etc., and then run everything else in legacy mode. If you prioritize legacy ROM then it will only go into EFI mode when there are no legacy formatted/option parts in the system, which is better for compatibility but functionally means never use UEFI mode.

[Kain]

Thanks.

What is the advantage of running/using EFI/UEFI over Legacy?

[caveman-jim]

If you have an UEFI mode mobo and EFI formatted boot partition and EFI compatible OS, you get faster boot times/secure boot compatibility/option.

Needs all the components to be compatible but can improve POST and Boot time in theory.

[Kain]

If I want to switch between the two settings, do I have to reformat Windows?

[caveman-jim]

Yeah, you need to format the disk as a EFI partition before you install windows. PITA to find out after you set everything up...

[Treeckcold57]

I had a hard time to figure it out how to install windows 7 in UEFI mode despite I tried to set UEFI only from Gigabyte mobo, but decided to back to default settings. So I googled it and I found this.

http://www.overclock.net/t/1156654/s...-for-ssds-hdds

I followed Sean's instruction by created a new folder "Boot"and copied files and paste into Boot folder, and then copied bootbootmgfw.efi and pasted into Boot folder. Renamed it to bootx64.efi and then plugged the flash drive into my rig and press F11 to select "UEFI USB hard drive".

I deleted all the partitions and created new and apply. Selected third partition to install. Now its show three partitions that mean I'm in UEFI mode.

Credit to Sean for all of this!

EDIT: fixed

[Kain]

If you install in UEFI mode, do you end up having to use a GPT partition instead of MBR or can you use MBR with UEFI too?

[Treeckcold57]

If you install in UEFI mode, do you end up having to use a GPT partition instead of MBR or can you use MBR with UEFI too?

Yes, I installed in UEFI mode and i checked diskpart, indeed its show the GPT disk.

[Kain]

Yes, I installed in UEFI mode and i checked diskpart, indeed its show the GPT disk.

Are there any disadvantages of running GPT? According to Sean on OCN, he recommends MBR unless you really need GPT.

[Treeckcold57]

Are there any disadvantages of running GPT? According to Sean on OCN, he recommends MBR unless you really need GPT.

GPT allows you to use higher than 2TB hard drive to boot and partitions can be up to 128. I'm might plan to purchase three of 3TB hard drives for ripped DVD movies and family backup data in the future.

[Kain]

GPT allows you to use higher than 2TB hard drive to boot and partitions can be up to 128. I'm might plan to purchase three of 3TB hard drives for ripped DVD movies and family backup data in the future.

Is that the only difference between GPT and MBR? When I was doing a fresh install of Windows 8 Pro, I "accidentally" installed in UEFI mode and ended up with a GPT partition for the system drive. When I went to Disk Management and formatted my secondary HDD, it formatted it as MBR. How would I tell it to format the secondary HDD as GPT?

[Treeckcold57]

Is that the only difference between GPT and MBR? When I was doing a fresh install of Windows 8 Pro, I "accidentally" installed in UEFI mode and ended up with a GPT partition for the system drive. When I went to Disk Management and formatted my secondary HDD, it formatted it as MBR. How would I tell it to format the secondary HDD as GPT?

Try this one guide, but it's for Windows 7...I'm not sure if it would be the same thing done to Windows 8. http://www.sevenforums.com/tutorials...-gpt-disk.html

Otherwise, try Sean's thread as I posted the link previously.

EDIT: Found information about how to convert MBR to GPT. How about this one? http://www.partition-tool.com/resour...o-gpt-disk.htm

EDIT2: Sean's Windows 8 Install & Optimization Guide for SSDs & HDDs

Burn the ISO to a DVD easily with the Windows Disc Image Burner: (link)

Burn the ISO to a DVD or USB with the USB/DVD download tool: (link)
With the Windows tool it formats the USB to NTFS, so if you are going to do a GPT install do not use the tool. For the UEFI to see your USB for a GPT install it needs to be formatted to FAT32.

How to make a bootable Windows 8 USB Installer with CMD:

1. Open and run CMD as Administrator
2. Type Diskpart, press Enter
3. Type List Disk, press Enter
4. Type Select Disk # (where # is the number your USB drive shows up as), press Enter
5. Type Clean, press Enter
6. Type Create Partition Primary, press Enter
7. Type Active, press Enter
8. Type Format Quick FS=FAT32, press Enter
9. Type Assign, press Enter
10. Type Exit, press Enter
11. Copy everything from the Windows 8 installation DVD onto the USB key (a simple drag and drop will do; if you have an .iso extract or mount first).

[Och]

So I'm bumping up this old thread.

I had to change some bios settings, so I was messing with them and then I saw this option that I have long forgotten about. I had it always set to Legacy ROM (which mind you is still a fancy BIOS that has pretty graphics and mouse enabled). So I set it to EFI compatible, restarted the PC - and was presented with blank screen for a while that finally emerged into a blank screen with blinking cursor. No option for me to get back into BIOS setup or anything like that. I had to actually clear CMOS with jumper to get back to the Legacy ROM.

Is this a normal behavior and I'm just doing it wrong, or is there something wrong with my BIOS?

[t3hl33td4rg0n]

So I'm bumping up this old thread.

I had to change some bios settings, so I was messing with them and then I saw this option that I have long forgotten about. I had it always set to Legacy ROM (which mind you is still a fancy BIOS that has pretty graphics and mouse enabled). So I set it to EFI compatible, restarted the PC - and was presented with blank screen for a while that finally emerged into a blank screen with blinking cursor. No option for me to get back into BIOS setup or anything like that. I had to actually clear CMOS with jumper to get back to the Legacy ROM.

Is this a normal behavior and I'm just doing it wrong, or is there something wrong with my BIOS?

I've never heard of not being able to get into BIOS when switching that mode, that is definitely not normal.

I'm no expert, but do have some experience with troubleshooting similar problems with my x64 based tablet, which has the EFI/BIOS options.

If your OS was installed via the legacy BIOS method then your HDD partition table is using MBR (which has some limitations, so it's not recommended anymore). EFI boot, which uses GPT and a special partiiton just for the EFI, cannot boot via MBR formatted HDD AKAIK.

The same is true in reverse, legacy BIOS cannot boot via GPT formatted drive because it's looking for the MBR, which shouldn't exist.


TLDR: Dont change the EFI/Legacy option on a computer with an already installed OS. Stick with whatever option was used when the OS was installed, regardless of the OS (windows/linux/bsd/etc). If you plan on format and reinstalling, switch it to EFI then before booting from your media.

If you installed via EFI, always keep EFI boot enabled and enable secureboot for added security to the EFI boot partition.

Ultimately, this isn't a setting you just change on the fly.