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GUID vs MBR

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Hi all,

 

I'm wondering what are the benefits of choosing GUID over MBR.

 

Please share your experiences with both. What do you think is better?

 

Thanks!

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GUID ftw.

You can create partitions when ever you want delete them and then extend the partition(s) back to the way it was with out losing data...

 

MBR.

You cant

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GUID allows you to resize your partitions without destroying any data. It'll also make OS X a little faster.

 

It'll be more difficult to dual boot windows on a drive with a GUID partition scheme tho, so I'd suggest using a separate hard drive if you can.

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It'll also make OS X a little faster.

 

Please explain to me how a table defining the start and end block is going to make a HFS+ file system faster?

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So far I hate GUID.

 

I had a horrible time trying to get it to work, my motherboard seems to hate it with a burning passion since it only mounts the disk when it feels like it when booting the DVD. Also Macdrive in Windows is extremely unstable with GUID it seems, I never once had a problem adding/deleting files on MBR but in GUID it seems to crash explorer.exe and make me restart the computer whenever I try to add a file bigger than 50k.

 

It also seems to be a pain in the ass to make one partition HFS+ and another NTFS.

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So far I hate GUID.

 

I had a horrible time trying to get it to work, my motherboard seems to hate it with a burning passion since it only mounts the disk when it feels like it when booting the DVD. Also Macdrive in Windows is extremely unstable with GUID it seems, I never once had a problem adding/deleting files on MBR but in GUID it seems to crash explorer.exe and make me restart the computer whenever I try to add a file bigger than 50k.

 

It also seems to be a pain in the ass to make one partition HFS+ and another NTFS.

Just to add another opinion...I've not had any of these problems on my system...although I'm dual booting from a separate drive, not the same one. MacDrive seems to very compatible, even for large files and the GUID setup was simple. Another plus for me is that since in MBR the efi info is written directly to the system partition, I was having only sparadic success with making bootable images with SuperDuper and CopyCatX. With GUID, since the efi is written on its own partition, I've not had that problem. YMMV.

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Don't know if it's possible or not, but I never succeeded !

 

By the way, is it possible to make an image of a well functionning Leo 10.5 install, using this guide, but formatting mbr, and restaure it to a Guid partitionned HD ? (I had no success with guid so far, just seen your update). If yes, what tool to use : Harddrive utility or another one ?

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Thanks for the informative response guys. It seems there are still some cons when using GUID.

Someone said that this benchmark results (I think it was mostly video benchies) were better when using GUID, but the Hard drive benchmarks were poor compared to MBR.

 

Anybody has the same experience with benchmarks?

 

 

Thanks again!

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I used the flat image with GUID no problem! Works great!

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another vote for guid here, but not because of performance. the selling point for me was the ability to add, remove, and resize partitions whenever i want without reformatting.

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another vote for guid here, but not because of performance. the selling point for me was the ability to add, remove, and resize partitions whenever i want without reformatting.

 

Sounds great but how many times do you actually do this?

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Sounds great but how many times do you actually do this?

 

its very handy to be able to add a 2nd partition to install a different version of OSX on the same drive for whatever purpose.

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Someone said that this benchmark results (I think it was mostly video benchies) were better when using GUID, but the Hard drive benchmarks were poor compared to MBR.

Hard to believe there would be any difference for day to day use.

 

GUID is just a partition table. Your partition is still formatted HFS+ and the FAT table for file entries is on there also.

 

I've had no issues using it.

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I used the flat image with GUID no problem! Works great!

 

What steps did you take to get it to work?

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Sounds great but how many times do you actually do this?

 

its not a matter of how many times i do it, its the fact that i CAN when i NEED to. for example: testing new install of osx86, or installing windows, or maybe you decide you want a storage partition to backup some important things if your hacked osx86 dies. theres countless reasons. why be constrained with MBR if you dont have to be?

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how many times?

 

an amazing amount of times. When I want to add a safe backup partition, vista partition, then delete them all, when i want to clone one half onto another half I can shrink the main down to the data, clone it onto a nother.

 

do guid

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What steps did you take to get it to work?

 

I imagine it could be done by using the restore function via Disk Utility. You'd need the flat image on another drive and then hook up the GUID drive as secondary. It should copy all data across to the desired partition...

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What steps did you take to get it to work?

You must have osx running on a machine first...

 

Hook up the drive to get the install usb...

Format to HFS+ with GUID (Do 2 partitions if your doing windows)

In disc utility after format, select restore and choose the flat image.

After the restore install Pc_EFI

Modify the Kernel and Kext's as needed then repair permissions

Install the drive in the machine and boot!

 

Thats about it! If your mobo supports usb booting you can try it that way first.

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Hard to believe there would be any difference for day to day use.

 

GUID is just a partition table. Your partition is still formatted HFS+ and the FAT table for file entries is on there also.

 

I've had no issues using it.

 

No, GUID is an entirely different method of HD data storage. They use smaller byte sectors for quicker read/writes, and thus the partition tables themselves contain less data.

 

MBR is about 20+ years old IBM legacy format, its been hacked and is technically been illegally modified for most current uses. I assure you, its a limitation that we've all just gotten used to.

 

That said, I use MBR because I like XP and use it quite often despite the better experience of using Leopard.

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No, GUID is an entirely different method of HD data storage. They use smaller byte sectors for quicker read/writes, and thus the partition tables themselves contain less data.

Not true.

 

A MBR partition table contains much less data than a GUID partition table. A GUID partition table actually holds a valid copy of a MBR partition table at LBA0 to help avoid issues if a MBR related utility is used. Every LBA entry in a GUID partition table is 512 bytes long, and you need a minimum of 3 LBAs.

(LBA0->MBR, LBA1->GPT Header, LBA2->Partition Entry)

 

Even if there was a partition table reading speed benefit, the OS very rarely reads the partition map no matter whether it be MBR or GUID anyways.

Any OS uses the File Allocation Tables (FAT) for access to files on the HD and you are still using the same filesystem.

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Just to add another opinion...I've not had any of these problems on my system...although I'm dual booting from a separate drive, not the same one. MacDrive seems to very compatible, even for large files and the GUID setup was simple. Another plus for me is that since in MBR the efi info is written directly to the system partition, I was having only sparadic success with making bootable images with SuperDuper and CopyCatX. With GUID, since the efi is written on its own partition, I've not had that problem. YMMV.

 

if efi is on another partition ( when using guid ) then does that mean you can ''restore system from time machine back up'' with lets say the kalyway 10.5.1 disk and not disturb the efi ''partition''? will this work?

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Someone must have benchmarked this! I really don't want to start over with GUID unless there are performance benefits. Anyone have any links to comparrisons? :)

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