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I have a workstation with 16GB of RAM, an 80GB boot SSD, and a software 4x 80GB array for scratch, running Windows 7 64-bit professional. The SSD is slower in sustained throughput than the array (especially on writes). It obviously seeks much faster. I generally use about half my RAM at any point. I've never seen it above 12GB usage.

This is only a question because space is at a premium on the SSD. I've shrank the pagefile to 2GB, but if possible, those 2GB would be nice to have back. Is moving the pagefile to the array going to be detremental to performance?

Bryan Boettcher
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  • Rule #1 of a solid-state drive: Never put a pagefile on it, or you're going to decrease the lifespan of the drive (given that said pagefile is used). Paging, even with a SSD, is still roughly 40 times slower than RAM. Get a mechanical hard drive for the pagefile to preserve the longevity of the SSD. – Breakthrough Dec 13 '11 at 17:28
  • @Breakthrough - Although the technical foundation is accurate, I think that's an unwarranted concern giving the average volume of writes involved in paging on most machines. I mean, Intel says you can write 21GB of data to their consumer-level drives every day for 10 years (!!!) without exhausting the write cycles. – Shinrai Dec 13 '11 at 17:42
  • Now, that said, in this particular situation you have another perfectly serviceable location for it with better performance than a standard hard drive (that swap array) so I don't see any argument AGAINST moving it. I can't think that it would noticeably hurt performance, and it would remove potential load from the SSD. I just don't think there's any reason to be alarmed about having it on the SSD. – Shinrai Dec 13 '11 at 17:45
  • @Shinrai: I agree people worry too much about write-cycles on modern SSDs. I mean, right now I'm defragging the thing (mostly for tail-packing purposes to reclaim more space -- 1.5GB and counting!) – Bryan Boettcher Dec 13 '11 at 17:50
  • @insta - There's no reason ever to defrag an SSD that I'm aware of, since it doesn't actually matter where in the NAND that the data sits. I'm under the impression that is just tossing write cycles into the garbage. – Shinrai Dec 13 '11 at 17:55
  • @Shinrai: I just said its for file consolidation purposes, as I deal in very small files that always get scattered over clusters wasting tons of space. I don't do it to improve performance, which means its a 6-monthly thing rather than a weekly thing. – Bryan Boettcher Dec 13 '11 at 17:57
  • @insta - I didn't realize that the excess space in partially-full clusters was wasted, I thought the drive firmwares were smart enough to work around this. That's a big oversight on my part, I'll have to read up on this. – Shinrai Dec 13 '11 at 18:01
  • @Shinrai: it's at the OS level. – Bryan Boettcher Dec 13 '11 at 18:20
  • let us continue this discussion in chat – Bryan Boettcher Dec 13 '11 at 19:08
  • At the OS level, the scattered clusters doesn't make a difference, since it doesn't translate to physical performance differences. – surfasb Dec 13 '11 at 22:36
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    @Breakthrough: That myth needs to die already. Corsair blog put 240TiB of writes and deletes into a 60GB SSD before it died. That translates to 20GB of writes a day, for 33 years. That's on a small 60GB drive also. Larger drives will see a longer lifespan. – surfasb Dec 13 '11 at 22:40

3 Answers3

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Quite bluntly, I don't recommend doing any of that. Leave your page file alone. Let Windows run it. It does so better than you. If you are that skimped on space, get a larger drive. Don't jack with Windows management of the page file. It's just worth it.

OG Chuck Low
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    I apologize.. I spoke to my senior admins to verify my answer and I was incorrect. It is apparently not a big deal to Move the SWAP file to another location. However both my seniors noted to Shrink it was indeed a horrible idea and to move it off the SSD despite your concerns not so good either. You want that on the fastest drive. Sorry for any bad info. – OG Chuck Low Dec 13 '11 at 17:38
  • Windows did a terrible job managing it, which is why I had to step in and do it myself. I leave it alone on mechanicals, but letting it take 24GB because "Windows knows more than me" is unacceptable on an 80GB drive. – Bryan Boettcher Dec 13 '11 at 17:51
  • Also, what constitutes "fastest drive"? The array destroys the SSD on sustained throughput. – Bryan Boettcher Dec 13 '11 at 17:55
  • There you have an excellent point. I have been discussing this with my mentors and really this is something that ideally you would already have some testing/knowledge of this. I didn't wanna keep spamming with comments or would have noted they also said your array isn't a "bad" choice although not usual. – OG Chuck Low Dec 13 '11 at 18:57
  • I have to agree that the size Windows decides to use for pagefiles is out of whack. – surfasb Dec 13 '11 at 22:42
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    @insta That's assuming that the pagefile consists of reads and writes of "sustained throughput". While I'm speculating, I'm inclined to think that reading and writing 4kb pages to and from the pagefile is going to lead to a lot more random I/O rather than sustained I/O. – Darth Android Dec 14 '11 at 00:11
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I would have said don't put your pagefile on the SSD, but this article at Microsoft suggests otherwise: Link

But if you've never used more than three quarters of your RAM, you probably don't really need a pagefile. Meaning that you should either move it to the normal hard drives (as it won't get used) or if you are feeling brave, remove the pagefile altogether.

Based on your comment on the other answer and on the MSDN blog post, I would say leave it alone* on the SSD!

  • Where leave it alone means constrain it to a sensible size (based on your other comments)!
Glorfindel
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Tom Chantler
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  • Of course, removing the pagefile has other consequences, since it isn't merely the lack of physical RAM that forces Windows to use the pagefile. – surfasb Dec 13 '11 at 22:43
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Did you think about RAMDrive and swap-file on it? Swap on (even "modern") SSD is bad idea for SSD-life anyway

Lazy Badger
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  • The lifetime has been discussed in the comments in the OP. I'm already running a ramdrive for other purposes, but I'd rather let Windows have access to the RAM. If I was going to do that, I'd just disable the swapfile. – Bryan Boettcher Dec 13 '11 at 23:20
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    Using a RamDrive for swap is one of the worst things you can do. – Darth Android Dec 14 '11 at 00:11
  • @darth-android - really? And you can prove it with facts, otherwise you're just yap? – Lazy Badger Dec 14 '11 at 17:26
  • Well, I don't exactly have scholarly articles on the subject, but it works out like this: "Free" memory isn't unused memory-- almost all of it is for disk cache and Window's SuperFetch. Memory management is always about keeping the most important data in memory, and forcing windows to keep that background process that runs once a week for 5 minutes in memory instead of caching the directory structure of My Documents (or something else used frequently), is bad. http://superuser.com/questions/314989/ http://superuser.com/questions/315347/ http://tinyurl.com/d6phqst – Darth Android Dec 14 '11 at 19:34
  • http://serverfault.com/questions/23621/ (Most appropriately, the highest-ranked answer specifically). If you'd like to discuss this further, we should take it to the [chat] – Darth Android Dec 14 '11 at 19:40
  • I like note from AngryHacker "I love it how everyone is saying "Microsoft has spent many hours thinking about this problem, so don't mess with it", yet completely ignore real world experiences". You can continue "In MS we trust", I prefer own brain and own experience. When you had last Windows-reinstall?! AMF! – Lazy Badger Dec 14 '11 at 20:20
  • My last windows install would be.... 4 years ago. Whenever the Win7 RTM came out. No noticeable performance degradation since then. And if you really think that you don't need the extra paged pooled memory and if you really think 8GB of disk cache isn't more useful then programs allocating memory they don't really use, the least you can do is just turn the pagefile off-- there is no difference between doing that and moving it into memory on a RAM disk. I don't "In MS I trust". I've actually studied memory management and understand how it works. I trust my own knowledge on how memory's managed. – Darth Android Dec 15 '11 at 03:55