Originally Posted by
unmesh
One thing I've never been clear about is whether you get more than the rated capacity if your data is highly compressible. I'm guessing not since the partition creation will preclude that.
No, the compression does not help capacity. It helps write-speed, and even more so, write endurance -- with heavily compressible data, Sandforce drives are the only ones which can have a fractional write-amplification factor, which in certain applications (writing a lot of text-heavy data, for one example) means they can potentially last a whole lot longer.
Similarly, if adds effective spare capacity -- which means a drive which is say, half full with heavily-compressible data like a lot of applications, or text documents -- won't see the "I'm full" slowdown to nearly the same degree as some other drives/models.
Originally Posted by
unmesh
This review shows that the write performance deteriorates with time though less at the 500GB capacity than at smaller ones.
http://hardocp.com/article/2013/01/0...8#.UbQTY_nvuDk
In general, steady state performance of SSDs is not specified by the vendors and not always commented upon in reviews.
Anandtech has gotten very good at testing the full-drive performance case; I'd encourage those concerned to look at those reviews.
That said, if you don't know why your use case needs extremely performance
relative to other SSDs, it's probably not a big enough difference to worry about -- these will still outperform disks in most cases (or at least match them, in certain write-heavy workloads which is the one area where they don't always outperform especially when full.) Use TRIM, and make sure to leave at least, say, 10gb free space (5-10% is better) and don't worry about it.
Really, this is rather like the concerns coworkers had when we first rolled out SSDs at work 4 1/2 years ago -- quite a number of them read about SSDs, and started doing weird things to extend the lifetime of their SSDs, many of which limited the benefit they got speed-wise or convenience-wise. None of which made sense, because:
* The SSDs were corporate-owned. If they ran out of write-lifetime in work use, they'd just get replaced. You didn't get to keep them after, and if you did, they'd be so obsolete you wouldn't want them as a system drive... I mean, I'd take a 160GB X25M-G2 -- I think we might even have a few G1s out there -- if we started throwing them out, but it would be to stick it in an enclosure and use it instead of a USB stick as a durable carry-around...
* There was absolutely no chance that a developer would run out of write-lifetime in the course of our 3 year refresh cycle.
We saw some drive failures, for sure, but every single one has been a catastrophic controller failure ("bricked drive") and not running out of writes.