# Does Older Hardware Not Support GPT?



## Peter_Used2know (Feb 12, 2015)

I have an older, quad-core HP Pavilion d4990y (desktop) that originally shipped with 32-bit Vista and 4 Gbytes RAM. After about a week of research I reasonably certain that I can run Win7 Pro, 64-bit with 4 x 2 Gbytes RAM (= 8 Gbytes). Given the anticipated performance increase, his seems like an upgrade worth doing to me, but I'd like more experienced and better informed people to give my plan a once-over.

1) HP shipped this model with 64-bit Vista, so 64-bit drivers are available, and I assume that if they work for Vista, they will also work for Win7.

HP Pavilion Ultimate d4990y CTO Desktop PC Drivers & Downloads | HP® Support

2) According the specs for this machine, it can take 8 Gbytes RAM:

Contact HP Support and Customer Service | HP® Support



> Maximum memory:
> 8 GB (4 x 2 GB) (64-bit OS)


3) BIG QUESTION

I've also purchased a 2 Tbyte HD from NewEgg, and somewhere I read that the hard drive must be "formated" GPT, which I had never heard of before, so I went reading up on it:

https://en.wikipedia.org/wiki/GUID_Partition_Table

At first I thought GPT was some sort of "upgrade" from NTFS because statements about it were phrased that you "format GPT", like you "format NTFS", but someone on another forum has told me that GPT is an alternative to MBR (Master Boot Record), and so I assume that you can have a NTFS-formatted hard drive that can either be formatted in MBR or GPT. Use of the language is real important to me for learning, so if someone can tell my how these ideas are conveyed I would appreciate it greatly.

But the main question is whether or not hardware compatibility is an issue with GPT. Can I assume that a system that shipped with a 64-bit Operating System can work with a 2 Tbyte hard drive formatted GPT? Also how does the GPT aspect of the formatting happen? Is it a standalone operation prior to the O/S install, does the Win7 Pro 64-bit give you the option during O/S installation, or is it just assumed and happen silently in the background during installation, or some 4th option I haven't thought of?


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## spunk.funk (May 13, 2010)

You cannot install Windows OS on a GPT initialized drive unless your motherboard supports new UEFI Bios, and you are installing Windows 8.0 or 8.1. Which yours does not support. You can install a GPT initialized drive as a storage drive, just not as a bootable Windows drive. 
A 2TB drive does not need to be Initialized GPT, it still can be MBR and Formatted NTFS. Anything larger the 2.2TB would need to be Initialized GPT. 
According to your specs, you should be able to instal 8GB or RAM if you are running a Windows 64 bit OS


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## Stancestans (Apr 26, 2009)

You can actually install OS (must be 64-bit) on a GPT disk even if your bios is non-UEFI aka LEGACY. The requirements are as follows:

1. UEFI mode requires a GPT disk
2. A GPT disk requires a 64-bit OS (unless the disk is just for storage, then 64-bit OS is not required, post-XP) 
3. 64-bit OS DOES NOT require UEFI mode for installation to happen.

Therefore, if your bios has UEFI support and UEFI mode is enabled (it can be turned on or off as desired), then you must have a GPT disk and you must install 64-bit OS on it.

On the other hand, if your BIOS does not support UEFI or has UEFI mode disabled, you can install 64-bit os on a GPT initialized drive because GPT is a requirement for UEFI, but UEFI is not a requirement for GPT. I hope I'm this is clear enough. 

In short, you can either choose GPT or MBR initialized disk to install 64-bit OS even if your bios is non-UEFI/legacy (or has UEFI mode disabled).

Note that UEFI mode requires a GPT disk primarily because an EFI system partition is required to boot Windows in UEFI mode. This EFI partition can only be created on a GPT initialized drive by assigning it a special GUID and GUIDs, as you've already discovered, are a feature of the GPT partition table type and are not for use with MBR type disks.


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## Stancestans (Apr 26, 2009)

Stancestans said:


> You can actually install OS (must be 64-bit) on a GPT disk even if your bios is non-UEFI aka LEGACY. The requirements are as follows:
> 
> 1. UEFI mode requires a GPT disk
> 2. A GPT disk requires a 64-bit OS (unless the disk is just for storage, then 64-bit OS is not required, post-XP)
> ...


STRONG POINT OF CORRECTION! 
I grossly mixed up facts in the above quoted post, so pay absolutely no attention to it. Spunk.funk is right.

1. In order to install Windows on a GPT initialized disk, Windows requires UEFI. Since your pc doesn't support UEFI, you won't be able to install Windows on a GPT drive, but you can use a GPT disk for storage only (UEFI is not required for that). 

2. Window Seven setup doesn't support UEFI by default. You cannot boot off the installation DVD while in UEFI mode. To add UEFI support for Windows Seven installer, extra steps are required and you will need to create a Windows Seven bootable thumb drive with the 'tweaked' installation files. Windows 8 however, supports booting in UEFI mode out-of-box. No tweaking is necessary.

3. GPT is required for drives larger than 2TB.

All in all, you have to initialize the disk in the old msdos type (MBR) partition table if you plan to install Windows on it, but if you plan to only use it for storage, then you can initialize it in GPT (doing so is pointless if the drive isn't bigger than 2TB).


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## Peter_Used2know (Feb 12, 2015)

Okay thanks for both posts and both opinions (lol). I've got the message. I've also learned that GPT is only required on drives larger than 2 Tbytes, and since mine is exactly 2 Tbytes then there's no need to format with GPT. It was the 2 Tbyte maximum that started me on this whole thing anyways, so with that off the table, I'm good with using MBR. Plus I've been informed that Win7 Installer does all this automatically and behind the scenes and I won't have any choice anyways. I got the idea from spunk.funk's post that you can "pre-format" using GPT or maybe the idea is to migrate an installation from one computer to another but in any case if the bios/motherboard does not support UEFI then it's not going to be recognized.

Stupid side question:

If you physically install a GPT drive in a non-UEFI computer, will it be recognized in BIOS? Will it be recognized by a (for example) Win7 Installation and then get overwritten with MBR, or will the install fail, or what?


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## Stancestans (Apr 26, 2009)

> Stupid side question:
> 
> If you physically install a GPT drive in a non-UEFI computer, will it be recognized in BIOS? Will it be recognized by a (for example) Win7 Installation and then get overwritten with MBR, or will the install fail, or what?


Yes, it will be recognised in BIOS. As far as the BIOS is concerned, it's a HDD. 

Yes, it will be recognised by Windows Seven installer and it will issue an error stating the selected disk is GPT. It will go as far as the partition selection screen (where you get a chance to create, delete, format and select a partition on which to install Windows) before issuing that error message. Basically, the installation fails with this error message at that particular stage (of partition selection).

I'm not sure if this partitioning screen let's you initialize the disk in MBR, I've never seen that option there and I don't know if it does it automatically for an already initialized disk (it does it automatically for an uninitialized disk), but I'm sure that the disk MUST NOT contain any partitions in order to convert it to MBR from GPT or vice versa. That means all partitions on the disk must be deleted before converting it from one partition table type to another. I've only done this prior to starting Windows installation, either using a pre-installation environment or from a loaded OS.


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## Peter_Used2know (Feb 12, 2015)

Cool, thanks for the information. I feel lucky to have the benefit of two people's high level of experience and understanding.


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## Stancestans (Apr 26, 2009)

Sure, I'm glad we could be of assistance. Your welcome.


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