What do fellow users feel about the strategy of having a dedicated OS hard drive for a PC? Basically all the Windows and Program Files are on one, high performance, disk whereas your data is stored on a another, larger, hard drive?

Does this see performance improvements? If so, What type of HD is best? I was thinking 1/1.5 TB HD for the content and a Raptor for the Windows Install?


7 Answers 7


It's a very good strategy. Not only the system performance will improve, but backups will become much easier. You can reformat your system drive any time without losing your documents.

For a fast system drive you can't find anything better than Intel's or OCZ's SSD, but they might be too expensive. Raptors' got much better $/GB ratio.

Important thing to know that SSDs come in the same package as HDDs. Same size and shape! However, SSDs are usually 2.5" form factor (like notebook HDDs), so they are smaller than a typical desktop HDD. Since most PC cases are designed for 3.5" form factor (typical desktop HDD) you need a drive bay. (Thread about this.)

This is a better approach than creating separate partitions because you can buy a very fast, but small drive and you can store your movies, songs, etc. on a slower, but much cheaper and bigger drive. This way you save money and you get a very fast system.

  • Would they fit into a normal PC tower?
    – Damien
    Commented Jul 20, 2009 at 13:31
  • I think 2 or 3 drives usually fit into a normal PC tower. But you can always check. ;)
    – KovBal
    Commented Jul 20, 2009 at 13:33
  • This varies depending on the system. Most towers only include two hard drive bays, but give more than enough 5 1/4" slots. You may need to get a mounting bracket. Commented Jul 20, 2009 at 13:46
  • The only problem is apps that edit the registry will still need to be re-installed even if they were installed onto the 2nd drive.
    – ChrisF
    Commented Jul 20, 2009 at 14:11
  • He said he's going to install all applications to the system disk afaik.
    – KovBal
    Commented Jul 20, 2009 at 14:16

The performance considerations are marginal at best, on a very fast drive. I have done this for years and haven't noticed performance to suffer or improve either way. I don't benchmark, it's a waste of time when I know I've purchased high performance hardware to begin with.

Now, doing this on the same hard drive but separate partitions, that won't be as high performance as separate disks. But again, performance isn't the main reason why you would want to do this.

The primary reason is to separate your data from your operating system and programs. This is why many Unix systems have /home as a separate filesystem. OS upgrades don't interfere with your data. I've built my systems where "Program Files" was on a separate partition of the same disk the OS was on, and my data lived on a separate disk entirely. This made reinstalling the OS easy, but that practice is deprecated on newer Windows OS's. I don't install a lot of crap programs, so my OS doesn't get crufty, so I don't have to reinstall every 6 months to a year :-).

Nowadays with high speed gigabit ethernet and a basement available for noisy server systems, I keep my data on a separate physical system. Most of the data I'm accessing is media for playback on my HTPC, and gigabit is perfectly acceptable for streaming.


In response to Damien's question of So what does 2.5 compared to 3.5 mean?

2.5 and 3.5 refer to the size of the drive - 2.5" and 3.5", respectively. The standard form factor for drives is 2.5" for notebook/portable hard drives, 3.5" for desktop hard drives, and 5.25" for optical drives (CD/DVD readers and writers).

Most solid-state disks (SSDs) come in only the 2.5" size so that they can be easily put into a laptop (where the power savings are substantial). To put one in a desktop you'll either need a flat surface to lay it (not recommended) or a special mounting bracket. While I've never seen a 2.5"=>3.5" bracket, I have seen 2.5"=>5.25" brackets.

Installing it in the bracket for your desktop is simple enough: screw the SSD into the brackets, slide the bracket into your case, and then screw the brackets into place.


I do this on my home PC, and I don't have hard numbers to indicate a performance improvement, but it does give the advantage of keeping your data safe from any viruses or malware that might wreck your Windows install.

Of course, you can do this with multiple partitions on a single hard drive too, but I'd like to think that using multiple drives provides a performance improvement (especially if you put your page file on the second drive).

  • 1
    I thought there would be I/O improvements and also the Raptor Drives are high performance but low capacity.
    – Damien
    Commented Jul 20, 2009 at 13:28

Are you talking about Windows? Its an outdated strategy. Windows makes such heavy use of the registry. So if your installed apps sit on another drive then, because of registry data, important bits of the app are still on the os drive.

Use a separate drive for data (i.e documents, music etc) but not for installed apps.

  • 1
    The Applications would go onto the same drive as the Windows Install.
    – Damien
    Commented Jul 20, 2009 at 14:19

I use only a single disk but I partition it in two different partitions since my disk is never a bottleneck and I get the benefit of a "drive" to the operating system and another "drive" to my data.


This is just what I am doing, though for different reasons.

One common reason is to be able to repair one's data. The separation of OS & applications and one's data is significant enough to warrant different drives. However, this is particularly true with Apple computers.

My old tower Mac has a data disk in MacOSX's HFS+ format. This can be partitioned to allow the editing of movies in one partition, then moving the final movie in a standard format to a different partition, which will not be so fragmented.

MacOSX is on one drive, with a large, contiguous swap partition on another. Debian Linux is on a third drive. Many Linux applications, such as OpenOffice.org, have been ported to MacOSX. I find they run far more smoothly on Linux, and Debian Linux has libraries that allow it to read & write transparently to the HFS+ drive. There are several, less simple, options for connecting Windows & Linux; and it's important to write files in international standard formats. Linux has desktops that resemble any other operating system's.

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