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Camilo Martin
Asked: 2012-02-03 08:21:19 +0800 CST

Performance gains of putting Windows pagefile on separate partition (same disk)?

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I am making a drive image that will be deployed to several computers, and I'm tweaking it for performance. It is a Windows XP image.

Considering there is only one hard drive, will the machine gain performance if I place the Windows pagefile on a separate partition, possibly FAT16 (instead of NTFS as the OS partition)? I'm thinking of this because Linux does it, actually it uses the raw partition as "swap space", which is more performant (has faster I/O) than the default journaled filesystem (I expect FAT16 to be faster than NTFS too).

If this does make sense, how should I go about it? Another filesystem? should the partition be on the beginning or end of the HDD?

performance hard-drive filesystems windows-xp pagefile

6 Answers

  1. This doesn't make much sense. Also, by moving the pagefile off of the boot volume, you lose the ability for the OS to dump crash info in the event of a BSOD. This makes troubleshooting a pain. On top of that, I can't imagine that your performance would increase by any meaningful amount.

    Just leave it where it is. If you're paging a lot, solve the actual problem by adding more RAM instead of mucking around with arcane disk layouts.

    Unrelated side note: I really advise against new deployments XP. It's end-of-general-support and is within two years of ending extended support. Why wouldn't you be deploying Windows 7 at this point?

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  2. Best Answer

    There is no performance gain at all in putting your pagefile on a different partition on the system disk.

    There is a gain, instead, in putting it on a different physical disk, but only if there are no other workloads on it.

    Edit

    To address your comment:

    • Compression is a Very Bad Idea for a page file, as it needs to be accessed precisely at random offsets, which becomes awfully slow if you don't know where a given sector is actually stored on disk and have to uncompress the whole thing first.
    • Fragmentation is never a concern, because the page file is always created in bulk and can't indeed be relocated at all (defrag utils always show it as a big non-movable chunk of data).
    • Whatever you can gain from a greater (theoretical) disk speed is useless if the disk is being accessed at the same time by other processes to read/write data or system files.
    • Ditto for any (theoretical) advantage of FAT above NTFS. Which is, by the way, purely theoretical, as NTFS is in no way as slow as you think it is.

    Again: there is only one scenario in which moving a page file makes sense, and it's when it gets placed on its own physical disk.

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  3. As others have already said, there is no performance gain. Quite the contrary, you can expect a measurable drop in performance. The reason for this is that by having the separate partitions on the same disk you will cause the head assembly to move more than would otherwise be the case. The effect is the same as a heavily fragmented disk.

    This of course applies to anything stored in multiple partitions on a physical drive (or array) but is worse for a swap file because it is read and written to constantly.

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  4. Since the beginning parts of the hard drive are faster than the end sections, I just set up a partition at the beginning of my hard drive for the swap file; named it Swap and set it to drive B:...

    I have 8 gigs of memory, so set up an 8 gb partition at the beginning of the hd. I remember back when I had IDE hard drives, fat 32 was faster, so I set it for that also... don't know if that still makes a difference or not, these days.

    I guess I might lose a ~little~ bit of speed at boot time, but if the swap file is being used by the os it should improve speed generally during use.

    PS - with 8 gb of ram you can get away with disabling the pagefile, but I noticed a little bit of speed loss without one; since the pagefile holds all the most recently used files ready to load into ram.

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  5. Actually, there is one scenario where you may want to move the pagefile to another partition. A while back, I took over management of several older production servers that had a 3-disk RAID 5 container partitioned as C: and D:. Unfortunately, following a worst practice that was in vogue at the time, C: is only 8 GB, while D: is 128 GB. The space on the C: drive was close to being exhausted, and moving the pagefile was the only was to free up some much-needed space.

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  6. Actually there are a few reasons for doing this. What I typically do is research what the best practice is for that install (2012 is far different than prior, and prior they'd suggest different needs for machines with 32GB+ of memory to NOT do the 1.5x)

    1. Creating a partition at the lowest offset puts it on the faster part of the disk
    2. Forcing it to this partition at a fixed size prevents it from growing and fragmenting automagically

    Both increase speed.

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