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There is something I don't quite understand. I know a SSD helps with OS load times, but I'm not sure if all this boost is only noticeable/interesting when booting, or gives an all around considerably better experience thereafter.

I am interested in having a quick and responsive environment after booting, which leads me to think that it'd be better to spend the SSD capacity in my most used apps (and the page file? Another inside question) and not the OS itself. This, of course, means that I don't know just how much the OS reads/writes its files during normal usage.

So, how good an idea is it to dump the whole 11GB+ of Windows 7 OS into the SSD (considering the hefty price per GB of SSD capacity) if I can put up with the usual hard disk boot times? Is there any performance to be gained during normal usage if I dump the OS in the SSD?

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Having the swap file on the SSD isn't going to help unless you are running out of RAM (in which case it would probably help a lot). – Zifre Jul 9 '10 at 21:42
+1 Really nice question! Now that SSDs are becoming affordable (kind of) that's a question that naturally comes to my mind too. – dag729 Jul 9 '10 at 21:43
Zifre: In that case, wouldn't adding RAM be the cheaper and faster solution, and reducing or eliminating the pagefile in favor of more file space? – JRobert Jul 10 '10 at 18:53
I did think of that. However, I already had the SSD, and I was only deciding how best to use that resource without spending more on RAM (for the time being). The results, though, are extremely in favor of putting the OS in the SSD. – Kensai Jul 10 '10 at 19:34
I don't understand why this was closed. The question was not "do you like...?" but "are performance gains to be had?". The answers so far have been extremely useful, and our collective experiences have pointed us towards installing the OS in the SSD. – Kensai Jul 10 '10 at 21:46

The link posted by Harrymc is a good one. is pretty-much the definitive site for SSD testing these days. I have SSDs in 2 laptops and I can tell you the performance difference is very obvious. Even with an X25-M Gen 1 I haven't noticed it slow down. Both of my laptops boot much faster and are more responsive than my desktop which hasa faster CPU and 2x WD Raptors.

As for lifespan, that is not a concern. See for the maths on that one.

OS drives thrive on fast access times and small random read / writes which SSDs deliver vastly better than anything with mechanical moving heads. Sequential writes are actually often slower on SSDs than on spinning rust. OS drives don't tend to do a lot of that. If you're writing large, sequential files then add Raptor or something like that for them.

It is easy to over-think the leap to an SSD. I don't know one person who says moving their OS & apps to an SSD made their life worse.

Just do it.

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Thank you for your comment. I would like, however, know if you or your acquaintances have had the chance to test whether putting the OS in the SSD only helps with boot speed or during normal usage. I will get an SSD anyway. – Kensai May 20 '10 at 17:09
It makes a very noticeable difference to both. I ain't n'er goin' back to spinnign rust. Well, only for its capacity, not for its speed. – CAD bloke May 22 '10 at 2:45
+1 "Spinning Rust – Moab Jul 9 '10 at 22:46
up vote 4 down vote accepted

I ended up testing both alternatives. I can now say with confidence that the OS on the SSD gives far better performance (it feels better).

I later brought up the resource monitor to check the disk usage, and there is constant activity on OS files.

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Makes sense, your apps will be loading OS components as well as their own. Services running intermittently could be unloaded if their executions are infrequent enough. – Dan Neely Dec 2 '11 at 15:57

I think this page from AnandTech sums up quite well how an SSD can speed up application start times (after booting). It's difficult to say specifically how the chart would be affected if the OS was on a hard drive (without trying it), but I would always advise that it would be foolish to buy an SSD and not use it for the OS.

The only downside I can think of (other than using up valuable space) is if you use hibernation: some SSDs (mainly the Intel X25-M) can have a relatively slow sequential write speed, so it may take longer to hibernate than for a hard disk. (Note that the hibernation file must be on the boot partition.)

Also, if you are concerned about using up ~20GB of disk space for the OS, the newer SandForce-based drives claim to be able to compress data written to the SSD, such that a 25GB OS + Office install can be reduced to ~11GB of writes. This is good for performance and flash endurance, as well as using less space. However, I'd suggest that (as CAD bloke put quite well) the random read/write performance values should be the main criteria when buying an SSD.

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Interesting stuff. Anyway, I was thinking that probably the biggest performance gain (at least for many apps like virtual machines) is on the page file, which, by the way, people recommend to be located in a different drive than the OS. Although most common sense is being thrown upside down with the coming of SSD. – Kensai May 21 '10 at 3:48
The "CAD bloke" link is wrong. Could you please fix it? – harrymc May 22 '10 at 5:54
@harrymc I'm not sure what you mean - that link is supposed to point to another answer on this page. – sblair May 22 '10 at 9:59

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