Helping people with computers... one answer at a time.

There's a diversity of opinion on the topic. I'll look at why I recommend only a single partition per hard drive and what partitioning does and does not get you.

I have an Inspiron 1520 with XP Pro and have just reformatted (NTFS) my hard drive into C: and D: partitions ... and have gained a huge amount of speed from so doing. I originally did that to speed up response time, as well as to be able to repeat the process on C: before waiting so long again. The C: is 48.8 GB and the D: is 100.0 GB. I would like to be able to load some applications into the D: drive (which has some room available), but even when I specify D:, it seems to want to overload C:. I think it is because of the master-slave relationship of the two drives (C: master, D: slave). Can you please explain to me how I can better manage my resources? I also have a larger external hard drive... and I'm winding up with C: full to the point that I cannot defrag it. I was originally trying to get the operating system on C: and other programs on D:, so that I could reformat C: having only to reload the OS and not all the other programs.

Your question brings up a lot of really good issues – and even some differences of opinion amongst folks such as myself.

Partitioning a single hard drive in to two partitions is an approach that's advocated by many as being faster, making backups easier and just generally being the best things since sliced bread.

As it turns out, it's not something I think really adds a lot of benefit as a general rule of thumb.

About that "huge amount of speed"

To begin with, I actually doubt that it's the partitioning that got you any significant speed boost. There are so many things that change and get cleaned up when you reformat a machine that make things faster – everything from simply running less software initially to having the entire hard disk naturally defragmented – that I'm not convinced the partitioning had much of an impact.

In fact, the partitioning could actually have had a negative impact.

When you partition a hard disk, you're setting up two distinct physical areas on the media. As Windows operates, the disk heads actually now have to move farther as the system moves between accessing files on partition C: and partition D:. Depending on what you're doing, that could be a little (perhaps most of your work is naturally on C: anyway) or a lot (files from both C: and D: are frequently accessed simultaneously).

If it's a lot, that partitioning could actually be slowing your machine down, not speeding it up.

Installing applications on a drive other than C:

Some programs will allow you to specify that they be installed in an arbitrary location when you run their setup.

Some do not and can only be installed where they insist on being installed, typically C:.

For the ones that do allow you to specify an alternate drive such as D:, many will still install components on the system drive, C:, anyway. The installation destination really only controls some of the files.

Even for those setups that actually do, indeed, copy all of their files to the intended destination, they still end up making changes to the system registry.

You know, the system registry stored on the system drive C:.

This has nothing to do with a master/slave relationship - that concept doesn't really apply to partitions (and even most hard drives anymore). This is just about the C: drive – the system drive – being special.

Important. And special.

Those applications on D: when you reformat C:

Sorry to say, but particularly when you have applications that store information in the registry or files of any sort on the system drive, having the bulk of the program installed on D: doesn't save you from having to reinstall them all when you reformat C:.

You need to reinstall them all because reformatting C: made all of their information in the system registry disappear, along with any files that they might have placed there anyway.

Installing applications to another drive buys you exactly nothing when it comes time to reformat the system drive. The sole exceptions are what are called "portable" applications, which do not require that you run a setup program. (Most major applications are NOT portable and those that have portable versions are pretty clear about their availability.)

One for all, all on one

My recommended approach remains: one partition per drive (excepting system restore partitions.)

Thus, I would not have partitioned your hard drive as you have. I'd have set up a single partition and reformatted and reinstalled to that.

If you're simply trying to organize your files, folders are not only perfect for that, it's exactly what they're meant for.

If you're trying to make things faster, the benefits are questionable at best, and the costs are high, as we've seen.

If you're trying to make the next reformat/reinstall faster – well, by now, you can see that you haven't really. The best way to do that is to wait until after you've installed the system and your major applications take a full system backup image; then use that when the time comes to start over.

One exception...

If you have a lot of data – not software, not programs, but data files such as videos, documents, mp3s, whatever – it can be advantageous to place them on a separate drive or partition. That way, when you reformat your system partition (or restore it from a system image), you can leave the other drive or partition untouched and preserve the data thereon.

You can use a second partition, if you like.

My recommendation? Go for that second internal hard drive. If you've got that much data, this is one approach that could make for a noticeable speed increase.

Article C5378 - May 23, 2012 « »

Share this article with your friends:

Share this article on Facebook Tweet this article Email a link to this article
Leo Leo A. Notenboom has been playing with computers since he was required to take a programming class in 1976. An 18 year career as a programmer at Microsoft soon followed. After "retiring" in 2001, Leo started Ask Leo! in 2003 as a place for answers to common computer and technical questions. More about Leo.

Not what you needed?

35 Comments
Michael Horowitz
May 24, 2012 9:55 AM

Having two partitions is indeed the best thing sinced bread. Its the best way to enable image backups which are your best friend (not insult intended to dogs). Image backups also let you recover disk space from the hidden restore partition which is no longer needed.

Install all normal apps to the C disk and use the other partition for data files.
Portable apps that don't need to backed up often probably belong in the OS/C partition.
Portable apps that you want to backup frequently probably belong in the data partition.

My guess is that Leo stores most of his data files on a server on his network. In that case, his one partition is, in effect, an OS-only partition and lends itself to image backups while his network takes the place of a data-only partition.

Critical concept is NOT to store data files in the same partition as the OS. Oil and water.

Elie
May 25, 2012 8:25 AM

I really enjoyed reading this article it enlightened me, thank you.

Dashrender
May 25, 2012 8:28 AM

Hmm.. Michael, Can't say I agree with you there. If you want to create image backups they shouldn't be on the same physical disk as your OS and data. Backups (Images) should always be onto some other media. In your described case, if the drive fails not only have you lost your OS/Data you have also lost you backups/images.

I totally agree with Leo, 1 partition per drive (exception manufacture restore partition, OK there is a second exception now, windows (Vista and newer) now wants a boot partition of around 100-400 megs that is not part of the C: Drive so now you'll end up with two partitions).

After you have a single partition (or two in the case of Vista and Windows 7) create image backups to a USB attached or internally installed second HD (though this is really not recommended since you can't easily remove it for proper backup procedures) as often as you deem needed.

Hagan
May 25, 2012 8:47 AM

In 2010 I bought a Dell 1764 laptop with a 500GB drive. Dell had partitioned the drive so the operating system was on a C: partition, and everything else on D:. The C: was only 60Gb! Even though I was diligently installing programs on D:, the C: drive became 95% full after a year of use! I had to use Partition Magic to change it, which, thankfully worked. What were they thinking??

Ken Laninga
May 25, 2012 8:52 AM

YES, use a C and a D partition. On my ex-lappy, an Acer, I had all my data files on D. When it crashed, the man at Staples sent it out for repair. They wiped C (but not D) and reinstalled Vista. My D drive and all my data stayed intact. What a RELIEF!!

That implies you weren't backing up your data, which puts it at greater risk of loss from any number of causes.
Leo
26-May-2012
Walter
May 25, 2012 8:53 AM

Michael-couldn't agree with you more. I, too, back up the OS (100GB) onto the same physical HD (in addition to an external HD). In my years of experience I rarely restored the OS due to a physical failure of the HD but rather because of viruses/malware and OS corruption. (Especially friends' PCs). It's an extremely easy and fast process to restore from the second partition and in the event a new drive is needed, the OS can be installed on any drive 100GB or larger. Most users don't realize that an 1TB unpartitioned HD must be replaced by another HD or equal or greater size regardless of the amount of data on the drive.

Paul Ballou
May 25, 2012 8:56 AM

I can say from some painful experience and thinking I knew more then people such as Leo.
I have a set up with a 32Gb SSD as my "C" drive with Windows 7 as the OS. I then have a 2nd Drive that has 4 partitions, "drives D,E,F and G, a 3rd Drive with another 4 partitions, "drives H,I,J and K and finally a 4th drive with a single partition, "drive" L. I conjured up a somewhat similar arrangement as the poster layed out and
have all of the possible problems that Leo mentioned. For the last month, I've been short on "C" drive disk space and any deletions have only been of a very temporary benefit. Next week, I'll be replacing My "C" drive with a 450Gb SAS and reformating all 3 of the other drives. I do a lot of CAD and MCAD so I try to keep those programs and file seperate from the "C" drive.
As for placing all the other programs on other then "C" drive is both a hassel and sometimes impossible feat.
Paul B.

flatom
May 25, 2012 8:58 AM

I'm squarely in Michael's camp. For years I've had C: for the system & programs and D: for data files on one hard drive. A 2nd hard drive contains one partition with backups of selected files & folders on C: and D: as well as images of C:. Lately I've become cautious enough to have copies of the backups and images on yet another removable drive.

Since I'm running XP my images of C: containing OS and applications are less than 10 GB which I create about once a month. It's quick to create and quick to restore. Vista/W7 would be larger, of course.

I can't see any advantage to including hundreds of GB of data in the image. That's what the data backups are for. Plus, I can restore backed up data files easily without having to dig into the image.

John McCurdy
May 25, 2012 9:01 AM

As a computer consultant I couldn't disagree more with Michael Horowitz's comment. It was a good idea in the "old" days when backup drives were small, and it _might_ be a good idea if you have many hundreds of gigabytes of data files, or if you are technically skilled and have a special need. But for the average user who has less than a few hundred gigabytes of data it is a completely unnecessary complication that creates a lot more problems than it solves.

I've made quite a lot of money cleaning up the messes (lost files, duplicated files, incomplete backups, and lots of other problems) that can result from trying to keep your data on a separate partition and not having the knowledge or skill to know when something is going wrong with the process, such as when a poorly written program writes to the old default location instead of where it should be writing. So unless you truly understand what you are doing, I strongly recommend sticking to a single partition as Leo said. Just get a terabyte or larger external hard drive ($80) and a good imaging backup program (I use Macrium), and you'll have a far more reliable and easier to maintain system than if you try to use multiple partitions.

And, as Leo said, there is absolutely no practical speed advantage in using multiple partitions. Sometimes (and only sometimes) you can gain a little speed by putting the Windows swap file on a separate drive, but that is something that should only be undertaken if you have the knowledge and skill to fully understand what you are doing. And putting it on a separate partition of the system drive actually slows things down.

James
May 25, 2012 9:06 AM

Sure two drives is best. But years ago when all I had was one drive partitioned C: only, some virus or power shutdown, who knows, corrupted the file structures and most data was lost. So I partitoned the drive into C: & D: with D: being for data as Leo says.
to be honest, I experiment (or used to) with a lot of programs, installing and uninstaling No doubt I have brought many catastrophes upon myself! (but then you learn much much more). After that, my data was safe and stable, even if I corrupted the C: drive.
Conclusion: better than no partition; not a good as separate physical drives.

Jim
May 25, 2012 9:39 AM

About storing your data on a separate partition or drive; be aware that if you use Outlook it buries your email, contacts and calendars in a hidden folder on the C: drive, not in "My Documents". This can be changed, but if you reformat the C: drive without moving the files you'll lose them all.

Ken R
May 25, 2012 9:50 AM

I am strongly in favour of seperate partitions; I have my XP OS on C: (25Gb), data on D: (45Gb) & apps etc on E: (80Gb).
This way I can backup (i.e. not image) my data using incremantal backup and recover individual files easily if required, and an image of the System partition (C:) takes about 8-10 mins to make or restore, and it is usually the C: drive that has problems from viruses etc. These images are also quite small in size, the same speed & convenience benefits apply to de-fragmenting or virus checking the C: drive.
I can see no point in imaging all my apps which can easily be re-installed if necessary from the original discs.

Michael Horowitz
May 25, 2012 9:57 AM

CLARIFYING:

Image backups should *always* be stored outside the computer that is input to the backup. I thought that went without saying, apparently, it needs to be said.

As for restores, depending on the imaging backup software, you should be able to restore into a smaller partition or no partition at all. By "no partition", I mean that the image backup software can create partitions on a new virgin hard drive. By smaller partition, I mean that, for example, a 100GB partition with 40GB of used space can be restored to a 60GB partition.

Some people have mentioned second internal hard drives. With so many people using laptops, it's often a moot point.

As for the C disk partition being large for Windows 7, part of it is System Restore space which can be greatly reduced if you make image backups. Also, keeping data files on a partition where System Restore is turned off, further reduces the space needed by System Restore (no previous versions kept).

Critical point: OS and data are different things and need different care and feeding. For example, the OS partition should only be backed up with imaging software, while a data partition should never be backed up this way.

All this said, separate partitions for the OS and data is not appropriate for total non-techies. No doubt, old school apps such as Outlook are a problem. Personally, I use a portable email client that is very happy living on any partition.

Data partition should never be backed up using imaging software? I realize that "imaging software" has several different definitions, but in general I disagree. Image backups are a fine way to make sure everything is backed up.
Leo
26-May-2012
Jim
May 25, 2012 10:13 AM

KenR
I have the same arrangement, but do image the apps partition. The point of doing so is the updates, changes, apps that have been downloaded vs. installed from a disk, license codes, etc, all get reinstalled at once instead of having to do them individually--a task that can take days in my case. The only problem, as Leo mentions, is you have to reinstall them anyway if the C: drive registry is wiped. I slipstream Windows for the same reason--it can take a long time to download and reinstall all the changes.

Fred
May 25, 2012 10:34 AM

You're absolutely correct Leo. I use a 7200 RPM 80 GB drive for the operating system and a 750 GB drive as a data drive. This way my system is always light and when i have to reload windows, I don't need to save my files...they're already saved in another drive that can go from computer to computer. Having an 80 GB system drive leaves me room to use as a "foyer" for unprocessed data, so it stays there until I decide where to store it within the data drive.

Joe Thiel
May 25, 2012 10:37 AM

Re: Partition. Thanks for solving my puzzle.I too had put progs. on a separate partition and could not understand why they did not work after reinstaling windows, now it makes sense.
Joe

Paul Mierop
May 25, 2012 10:51 AM

I have installed a Solid State drive of 64 GB as my C:/ Drive with the operating system and a normal magnetic disc (500 GB)as the D:/Drive for Pictures and Downloads plus other Miscelaneous. What will happen if the 64GB get full because of Program files ? Can I transfer these to the D:\ drive ??. And what about the page file ?

Jim de Graff
May 25, 2012 11:05 AM

Because C and D are on the same physical drive there can be no master/slave relationship. A 50 gig C partition is certainly more than adequate for Windows XP (I used to have a 20 gig partition and I install a LOT of applications). If you are running out of space I suspect it is because your "My Documents" folder is on your C drive and you are storing your data files there. This can be moved to D by right clicking on My Folders and selecting the appropriate action from the context menu.

As for having one partition per drive, in your case I would advise against it. By moving My Dociuments to D you maintain a separation between your OS/Apps and the data. By imaging the C drive you can restore an old image to recover from a corrupt system without having to worry about backing up important files. If you have just one 150 gig partition you lose this ability unless you are willing to keep no data files on that drive. I maintain several PCs for family members. I have had to restore the C drive on several occasions and keeping the system partitioned as I do makes this job a heck of a lot easier.

Old school apps like Outlook are not a problem. Outlook, for example, can easily be configured to store its pst file(s) on D.

Mark J
May 25, 2012 12:32 PM

@Paul
It's not possible to simply move programs to another drive. You would have to uninstall the programs from the C: drive and install them on the D: drive. As this article states, not all programs allow you to do this.
Can I move an installed application to another drive? Because of the files an installed application usually leaves behind, it's prohibitively difficult move it to another drive.

reuben
May 25, 2012 2:40 PM

The practice of 'tech-savvy' friends of mine is that they partition their hard drives into 2 to 3 partitions. Their argument would be that if drive C: were to be infected by virus, all their files would be safe on D: and they would just reformat C:

My argument would be that if drive C: is infected, you can always expect drive D: to be infected too. So if you reformat and reinstall on C:, the virus residing in D: would again jump on to C:

Of course they gave me the evil eye and treated me as if I was the crazy one.

Mark J
May 25, 2012 2:52 PM

@Reuben
You are right. When it comes to viruses, there is little limit to what the viruses can infect, including any drives which are plugged in externally to the computer.

Jules Gagne
May 25, 2012 3:35 PM

I like having a smaller O/S partition and large program/data partitions, because it makes it easier to make image backups of the system partition, which after all is the most likely place that system errors and infections would cause corruption/damage.

Jim Hillier
May 25, 2012 3:49 PM

WOW. Lots of good discussion here, and lots of contradictory comments from the 'experts'. IMO, it's a matter where levels of expertise should dictate policy... horses for courses.

I agree with Leo in principle. For the vast majority of 'average' users one single partition involves less complications and is less susceptible to operator error.

That said, I do utilize two partitions for separating data from the system. I'm heavily into video and movies so maintaining all that data on the system drive would be impracticable for me. However, I have not reconfigured nor altered any settings for personal/user folders. I simply created corresponding folders on the data partition and periodically use the "Move to folder" right click menu option to transfer files over - and ultimately to an external drive. I'm well aware there are more efficient methods but my way leaves me in control and is pretty much idiot proof.

As for the imaging aspect, again there are pros and cons. Maintaining a single partition ensures that ALL files are included (backed up) in an image. Sure, the image file is larger, making save and restore options more time consuming, but at least the personal data is backed up somewhere.

Other comments have suggested that imaging negates the need for System Restore and/or the recovery partition. That, IMO, is bad advice. It would be too lengthy to fully explain the reasoning here, suffice to say that people should always tend toward more backup solutions, not less.

Mike Noonan
May 25, 2012 4:42 PM

In these discussions, most often rotational delay is not mentioned. "On average" the sector you want is half a rotation away. You can calculate the delay by knowing the rotation speed of the drive.

The drive only has one arm to service all requests. With multi-core processors the requests "queue" up against the arm.

Competing requests can cause "thrashing" - I want it, no I want it, no I want it..

With partitioning, you will guarantee a longer seek due because of the partition boundaries.

Disk drives use 512 byte sectors as the smallest writable write size. A declared 4096 block of 8 sectors will write that block as 8 contiguous writes on "one" Write. Using a small block size may result in many Writes that altogether may not be contiguous (consider writing a 1 MB photo in a single Write).

Noncontiguous Writes result in non-contiguous Reads; these Reads may reference a bit map table to re-assemble all the blocks.

Disk drives are the third slowest devices of the computer.

It's complicated. I haven't even gotten into cylinder check, track check, recalibration, and spare sector tracks.

daffey
May 25, 2012 7:23 PM

I think what Mike (before this comment) is saying, is 'On one hard drive you have a path comprised of drive memory, where the data coming off the heads is accumulated, and an actuator with the heads mechanically attached and you can only use that path for one operation at the time. So splitting the drive via partitioning will not speed up the transfer of data, and probably negatively impact access time. This is my opinion as well. For more speed, you should gain more by adding drives which gives you more paths.

However, if you are 'cloning' a Vista or Windows 7 system as a backup option, then you want to 'partition' the backup drive to the same size as the original drive is. If the backup drive is larger than the original then you run into issues when/if you try to 'restore' from your backup at a later date. I don't know the intricacies, but apparently Vista and W7 write info at the end of the drive that can get lost if you change size when cloning.
There is an advantage to reinstalling both the OS, and programs to speed up your system; If you can't remember what programs you had and need, you probably were not using them, and don't need them and their start-ups plugging up your machine. Additionally, your likely to reinstall newer more secure versions if you download them.

Rick
May 25, 2012 10:24 PM

Partitioning for performance is a highly debatable issue and almost certainly has no clear cut answer.

But I have to agree with Michael H., user data and OS’s do not and should not be, mixed. If the OS goes down hard any and all user data can be lost and today between pictures, eBooks, movies, etc users can accumulate so much costly and precious data it should always (imo) be kept separate from the OS. I personally even go so far as to move my email-store off the system drive, as well.

And while keeping user data separate USED to be tricky for the average user to deal with, a good setup and a little training usually let them deal with this. However, recovering data after a system crash/malfunction was almost impossible for them handle without help.

And the reason I used the past tense, is because with Win7 migrating user folders to another partition is so easy and transparent to both users and their programs, it is just incredible. You just have to right click a user file, select the 'location' tab and select the new location. Since this is done as a system option programs have almost no problems (nothing is perfect) saving and accessing to these 'relocated' user folders.

And if (again Win7 is just so stable) a crash happens or the system needs to be 'freshened up', all user data is safe in one central location ready to be re-linked to the system. (It still needs to be backed up, of course!)

The only real issue I have seen with partitioning is that it is easy to give the system partition too little space. So, if you can’t give 100gigs to the system partition (talking modern systems here) don’t partition and just buy another hard drive and move your user data to that drive. And if you have an older system and a smaller drive (smaller than 100gig) buying a second drive is probably the best way to go as well.

Cyba
May 25, 2012 11:07 PM

I reformat every 6-9 months or whenever I feel Windows has sufficiently 'sludged up' (yes, I run some very good 'house cleaning' tools, auto- defrag, etc.) using a pristine WN+main apps mirror image taken from an original/new install. Therefore I have two (sometimes more partitions on very large drives) so the data folders on the secondary partition(s) - which are backed up elsewhere - are not affected by the OS+Apps reformat. Seems logical to me.

BAW30s
May 26, 2012 1:40 AM

Let me add my voice to Leo's and the commentators who recommend a second hard drive. I was given the computer I am using now: it is reasonably fast, but only has a 40GB hard drive. I added a second 150GB hard drive which I use for data and the paging file; I may upgrade this further soon. This arrangement greatly speeded up work, separated the data from the OS, and created a great deal of space: it's ideal. Unfortunately, the original questioner's computer is, I think, a notebook!

Ralph
May 26, 2012 5:25 AM

Thanks Leo. Just Thanks, you are appreciated.

Max
May 27, 2012 12:29 AM

I've always partitioned in the past and continue to do so. Depending on the size of the drive and preference at the time the number of partitions and sizes varies. I usually like to partition to help organize my files and to keep data separate in case I need to reformat and reinstall. At the moment I have a single 500 GB hard drive split into three partitions: OS, DATA, BAK. It's a really subjective issue.

Tony
May 29, 2012 9:22 AM

I have my 1Tb hard drive partitioned into 16 (yes SIXTEEN) different partitions with key and different data on each.
I run FIVE different operating systems all on separate partitions with 4 of the 5 being HIDDEN at any one time.
The remaining 11 partitions provide select KEY data for each system.
The base/boot partition (always C of course) has NOTHING BUT the boot+OS on it plus vital C-drive folders like the registry, docs & settings and programs. So if it crashes it takes nothing vital with it!!
Documents are all on a different (E) partition with ALL applications on the D partition.
My page and temp files all have their own partition too?
I won't go on except to say the overall system is GREAT, works FAST, well and securely.
It is really EASY to install or recover if there is a problem and MUCH easier to back up!!
If you have never done it... test/try it and see if you agree with me!?
Good luck
Tony (my 60th year in IT)

Shibu
May 30, 2012 9:18 AM

As usual, an excellent article.

James Ferris
May 30, 2012 3:02 PM

my response?
Depends...
Personally, I run my system with a 1TB hdd as:
- 60 GB root
- 10 GB temp
- 150 GB data
- (all the rest) media files
I learned this from linux, actually. Separating the temp / pagefile does not actually speed things up, but it can make cleaning and maintenance easier.
The 60 GB root system is about enough for install of almost all usable programs. Specialized media software (eg editing video files...) may require extra, so set up this partition as needed. Note this method does not speed up the system... it does make system maintenance faster - things like defrag, and restore points, and data backup are potentially more manageable.
However, the caveat.... I only recommend this for persons willing to actually do the required maintenance, and understand what is required for each stage. Once set up, it can be much easier to perform. Backup is much easier to manage this way using the free tools available to XP. But it does require an organized mind. (smile)

PC Doctor
July 4, 2012 9:03 AM

I'm a believer in partitioning too. I'd don't want to jump into conclusions. It just seems that a partitoned hard drive lasts longer because it's surface gets used more evenly, perhaps, versus an unpartitoned drive where most data gets written to the same sectors over and over, and some are left unused. I have a couple 5-6 year old maxtor 200 gbs drives still going strong. I use five partions. g/windows
f/temp internet files and downloads, e/emails and documents, d/songs, c/programs
I do have a backup of all of the partitions, c and g not too often since they don't change that much, just some updates.

vibhash
September 19, 2012 9:44 AM

dear sir i have 250 gb hdd. i have done same equal partition. and i want to make all partition bu table for different operating system installation with them. can i do this......

Comments on this entry are closed.

If you have a question, start by using the search box up at the top of the page - there's a very good chance that your question has already been answered on Ask Leo!.

If you don't find your answer, head out to http://askleo.com/ask to ask your question.