20 minutes of random writes and sequential write performance drops by over 85%! Obviously that's a problem with that controller. But that's the context in which I say that a performance loss of 33% isn't that big of a deal. Sure, if it keeps dropping at this rate, you have a problem. But we don't know that.
That test, I believe, is much more hard a task than what I have given the drive to work with...I did run another CrystalDiskMark bench and the performance did drop a little more on some tests, while others showed a little better results...I'm not arguing that this is a work in progressive degradation...it was run minutes after another test, so that could have affected it...but it does seem like it is getting worse, albeit not in that pace, i.e. 1/3 decrease with regard to the initially measured performance every couple of days...
Actually, As SSD benchmark did measure a 60mb/s drop compared to the initial results in the sequential write test the third time round...that's 2/3 degradation...it was not confirmed by CrystalDiskMark
It's not clear you actually have a 33% performance loss. How does your test work? Does it apply to actual performance? I don't know. Some tests do not show any performance degradation and some do. That tells us that compression interacts with performance degradation and that we need to make sure we're not comparing apples and oranges before jumping to conclusions. In the link above, a SandForce drive's performance appears solid under use but I suspect the result might be bogus (like your "0Fill" test).
This is in fact one of my stated questions in the first message...how should I value these results? Do these tests measure performance in a way that other tests don't, is it actual performance drop or not? I can't answer these questions...certain remarks about CrystalDiskMark's reliability have caught my eye, but I haven't really read anything negative about As SSD Benchmark.
And it's not clear that TRIM doesn't work. Why do you say the effectiveness is 0%? What you have noticed is that idle garbage collection over 8 hours doesn't change the picture. But we don't know that it's supposed to: garbage collection might be supposed to recover from states in which performance is worse.
Well, I did try closing all programs and triggering the TRIM command by deleting a folder/files on the SSD just in case it did not kick in by itself (I read that in a bit-tech.net article), the pc was left hours idling and yet no increase in performance was measured.
After that, assuming that TRIM might not be actually working, I logged off for 8 hours and then tested again, assuming that GC will take TRIM's place instead, but had absolutely no performance increase.
Given that the tasks that might be causing the write speed decrease were closed, TRIM or GC should be able to make up for a certain, minimum amount of performance drop...
I have never read, anywhere, that GC has a level of SSD performance set, above which it will not kick in...so, even if this is a heuristically clever observation, it seems unfounded...unless you have come across any such reference, of course.
I have also read of differing level of performance restoration, but I have not read of total lack of any kind of compensation...
Specifically: can someone confirm that their used SandForce drive has a better performance than yours when performing the same tests? Or could you run the same tests as someone else and compare? It's pointless to worry about your chipset, drivers, whether TRIM works and so on if the performance degradation you get is normal. Even then, the difference might come down to the firmware or the version of the controller. I understand OCZ has distributed different SandForce firmwares or something.
I have read threads at local forums about SSD performance overtime, but I have not come across any reference to such a drop in such short time with a TRIM enabled SSD (if not related to alignment problems or reformats etc) if time for restoration was given...I still haven't found an example on this same drive, though, and many comparable details are missing...I have posted in the Corsair forums, no real answer yet...there is at least one similar case, not much input on that either...
...even if the performance degradation I get is normal (which I doubt it is, since other people who work with large excel, powerpoint files, that do image editing etc have not testified to consistent and
persistent performance drops with their TRIM enabled drives) absolute lack of any kind of performance increase in idle or during log off might point to a problem...
As I said above, the issue at hand is the level of performance degradation (if this actually occurs outside benches) with regard to the time-length in which it was measured and to SSD usage during this time + lack of performance improvement after logoff or idling...
If other external factors might be relevant, I would look to SB chipset and mb bios...but still haven't found an identical or greatly similar example.
Finally, there's the possibility that your write tests and not your normal use of the SSD degraded the performance. Writing is what degrades performance and you can't test for the performance degradation you suspect without writing which is a bit of a conundrum.
Then again I suspect filling much of the drive and then using it for heavy browsing cache could also degrade the performance somewhat.
Valid concerns, but if I had to make an assumption based on my experience, these would not be my top guesses.
First of all, if these same tests were at fault, then we would have to assume that after the first two days since the install, running the benches accounted for much of the measured 1/3 drop...
Furthermore, I have run two CrystalDiskMark tests close to one another with some small differences...if these played any substantial role in reducing performance, this would be clearly measurable between any two runs of these programs.
I have tried to minimize the number of benchmarks tests, exactly because I could be producing the issue I am trying to identify and overcome...but these benches have been few and generally scattered, so I would not count them as main factors here.
The heavy browsing is one of my concerns...still, since Firefox has been left with its given number of open tabs during an extended period of time (during night-time), so that some data would remain in the SSD but there would be no more writes running, one would expect TRIM to do its thing and give even a little, but measurable performance increase. This has not occurred, and although I am not at all willing to exclude it from the list of determining factors - after all this is the application I have been using consistently - I am more suspicious about the functioning of TRIM itself.