Some questions regarding GPT, UEFI & Triple Booting

Hello guys.

I plan to triple boot Windows 8.1 Pro, Mac OS X Mavericks and Ubuntu 14.04 TLS on my machine.

I just had a few question regarding the same and some questions about UEFI & GPT.

Now, I'm going to format my entire drive and install Windows 8.1 in UEFI mode. So the hard disk will be automatically formatted to GPT instead of MBR right?

Also, my graphic card (MSI R9 270X HAWK) doesn't yet support UEFI/GOP so even if I do install Windows 8.1 in UEFI mode, I can choose not to use the UEFI option?

My hard disk being GPT formatted during the Windows 8.1 install in UEFI, will I have to apply any patches to install OS X (which will be on a separate partition)?

Should I install OS X first as it uses GPT and then install Windows 8.1 in UEFI mode on a separate partition?

Lastly, after installing OS X and Windows 8.1, how do I install Ubuntu in UEFI mode (if it supports UEFI) and configure the boot menu so that I can choose which OS to boot into?

Thanks in advance.

Regards,
Yash Shah

I don't know about Linux/Mac, but here is some info about UEFI/BIOS boot mode: link

Don't confuse the UEFI and Windows 8 Secure Boot modes. You can use UEFI without using Secure Boot. Because of the Graphics card, you will be able to use UEFI as long as the Secure Boot is turned off, which normally means enabling the CSM.

As far as I know, all three OSes use UEFI, but having a Boot menu may be a problem. I just use the Boot Device Menu to select booting between Windows and Ubuntu. I have no experience with OS X and do not know if it will be able to use the Windows EFI partition for booting.

I would recommend The rEFInd Boot Manager. It is also easier (I think) to install OSX first and obviously if you are using a mac it will be installed anyway. Adding linux after should be easy.

You don't give any specs but Windows will not install using a pre EFI 2.0 which includes most macs prior to 2013. If this is the case you will have to install Windows using a hybrid gpt/mbr partition which is described in the link above. This is OK but is problematic if you ever change partition sizes as you'll have to synch the mbr and gpt tables as changing partitions in OSX will not update the mbr and changing them in windows will not update the gpt. You then can end up overwriting the other OS data if you are not careful. You can use gdisk GPT fdisk | SourceForge.net to fix this if you later change partition sizes.

You might like to consider running windows and linux in VM under OSX as it would be easier. Don't be tempted to try to run OSX in VM as while it works the graphics support is pitiful.

Edit: This is my set-up which works well dual booting.