GPT versus MBR for W10 boot SSD?

I have a mixture of W10 Pro and Home systems booting from SSD's of various sizes. Several of the newer systems I had preformed a clean install of W8 and set the SSD up as GPT. With the auto update feature for W10 I have ended up with a couple of "old" systems running W10 on MBR formatted SSD's. I'm curious, is there any reason/advantage on why I should do a clean install of W10 on the MBR drives and convert to GPT. The systems in question have the latest and greatest MB's and BIOS's so they should be able to take advantage of what UEFI has to offer? All of the SSD's are 240GB so the number of primary partitions is not an issue.

As long as the System supports UEFI then you can convert HDD / SSD to GPT
UEFI=GPT > 128 partitions + support over 2TB
BIOS=MBR > 4 partitions

Ken429 said:

With the auto update feature for W10 I have ended up with a couple of "old" systems running W10 on MBR formatted SSD's. I'm curious, is there any reason/advantage on why I should do a clean install of W10 on the MBR drives and convert to GPT. The systems in question have the latest and greatest MB's and BIOS's so they should be able to take advantage of what UEFI has to offer? All of the SSD's are 240GB so the number of primary partitions is not an issue.

The mix of "old" and MBR suggests to me the BIOS on those 2 computers may not support anything other than MBR. If they are working I'd leave them alone. But then the mention of "latest and greatest MB's and BIOS's" suggests the computers are not all that old. I've run Win10 on a Desktop that original came with WinVista and a Notebook that came with WinXP, as long as the hardware met the system requirements there should be no major problem but as with any upgrade the drivers for the motherboard may present a challenge. So far with 6 Upgrades I've had only Bluetooth driver issues and Dell provided those updates.

In terms of performance GPT may shave a couple of seconds off of boot time, but MBR is slightly better otherwise.

In terms of recovery from data corruption GPT has better capabilities than MBR.

I would leave it as is, YMMV.

Thanks for the responses.

The system I'm questioning has a ASRock Fata1ty Z97X Killer MB that inherited an older 120GB SSD boot drive that was formatted as MBR. I just cloned that drive to a 240GB Sandisk Extreme Pro and of course got a 120GB boot partition and a bunch of unallocated space after the 450MB partition.

My question still is: will a GPT formatted drive give me any additional features under W10 on this system? There must be a reason MSFT wants to default to GPT when installing W8 and W10 on a new drive or a drive that has all the partitions deleted before installation? I have been using this system as a test platform so a clean reinstall should not be a major issue as long as the information on the internet is correct about MSFT not needing a W10 key once the system is registered (it is) as a legitimate W10 upgrade.

Ken429 said:

My question still is: will a GPT formatted drive give me any additional features under W10 on this system?

No, there are no 'special' Windows 10 features for GPT beyond GPT's inherent features already pointed out in this thread.

Ken429 said:

There must be a reason MSFT wants to default to GPT when installing W8 and W10 on a new drive or a drive that has all the partitions deleted before installation?

Because UEFI and GPT are now, essentially, the standard for new machines.

Ok, thanks for all the input. I guess the advantages of GPT make it worth the effort...AND... I really wanted to try a fresh install of an Updated W10 system to see if it stays registered properly. If it doesn't I'll be back!!

Ken429 said:

My question still is: will a GPT formatted drive give me any additional features under W10 on this system?

Secure Boot only works in UEFI Boot Mode, when you enable Secure Boot in your PC's UEFI firmware (BIOS) settings. But if you have an OEM PC that came with Windows 8/10 64-bit preinstalled, then Secure Boot is turned on by default.

Microsoft designed Secure Boot to protect the computer from low-level exploits and rootkits and bootloaders. A security process shared between the operating system and Unified Extensible Firmware Interface (UEFI, replacing the BIOS), Secure Boot requires all the applications that are running during the booting process to be pre-signed with valid digital certificates. This way, the system knows all the files being loaded before Windows 8/10 loads and gets to the login screen have not been tampered with.

If a bootloader has infected your computer and it tries to load during the boot-up sequence, Secure Boot will be able to undo all the changes and thwart the attack. Having Secure Boot means it is that much harder for attackers to try to compromise the start up sequence.

By the way, it is possible to convert the partition table from MBR to GPT using the tool gptgen: Here you'll find a quite comprehensive guide as well as a download link. I used this myself to convert my non system disks.

warning: Don't try it without backing up all your data. The tool works but messing around with partition tables can easily lead to complete data loss!

What's more I highly doubt this will work with system disks. But if you have got one or more separate data disks it is a very handy tool.