Kdo říká, že to trvá řádově milisekundy? Zkoušel jste to? Ta operace je schopná u Samsungu trvat i mnoho sekund, záleží jak moc musí po sobě uklízet. Po celou dobu je zařízení busy :-) a nedá se použít. To jsou ty propady výkonu u běžného používání.
To bylo shrnití z http://forum.root.cz/index.php?sid-forum=4ve1oug3l5lgsqhkfetcdnhho0&topic=12339.45, kde to psal uživatel dmatt (13. 12. 2015, 11:13:35)
Technicky spravi s diskom stary TRIM to iste co novy queued TRIM, len ten stary moze byt o niekolko miliseknud pomalsi. Beznemu uzivatelovi spusti LINUX TRIM prikaz raz tyzdenne a bude to trvat menej ako sekundu, nech uz sa pouzije ktorakolvek verziu TRIMu.
Jenže dmatt vaří z vody 
https://www.reddit.com/r/buildapc/comments/3kj6li/does_the_samsung_850_evo_have_the_same_issues_as/cuxv6ygProsím, oprav mě jestli to chápu špatně. Takže to je celé navrženou technologii, takže se vlastně ani nemusí řešit, jak se dělá TRIM. Díky tomu, že třeba ten mx200 používá pseudo SLC, tak ten disk je "skálopevnější". :-) Jestli někdo přijde s tím, že to je zase jinak, tak mi další disk vybere přítelkyně a ta to vezme podle barvy :-)
The design was flawed and not actually fixable.
Which I've been telling people for almost a year now...
despite there being literally hundreds of threads claiming 'Samsung fixed it!'.
Fortunately for you, the 850 evo uses an entirely different memory design,
Both designs employ 3bit TLC.
However the 850 series has a significantly larger planar design of 40nm compared to the EVO's 19nm, and employs VNAND charge traps instead of NAND floating gates, almost inadvertently fixed the issue that is inherent to the design.
SSDs store information in memory cells with floating gates, that store varying charges at fixed voltages.
The charges naturally degrade/leak over time due to a plethora of factors although this is rarely a problem.
Some of the fastest SSDs employ SLC, single level cells, that only have one (21) voltage state, allowing it to hold two bits of information: 1 or 0. $3/GB.
This is easy to read, hard to mistake, and has very high endurance/longevity and write performance.
It's rarely found outside of expensive enterprise solutions due to the price however. You can find pseudo-SLC in the 840/850 EVO/PRO as LPDDR caches and in the MX200 as dynamic write acceleration.
----tady se spletl viz dalsi prispevek ----
Just a quibble - the 850 Pro uses MLC (and 3D-VNAND at that), not SLC. I'm not aware of any SLC using the V-NAND structure, and you'd be hard-pressed to find a consumer-grade drive using it.
Additionally, the controller cache in the EVO uses Low power DDR2/3 depending on model. It's not clear from anything I've read what that uses, but it may be SLC.
SLC is generally enterprise-grade hardware and is simply not cost-effective per GB for most home users, except in special circumstances.
----
Then you have MLC (multi) with 22 voltage states: 00, 01, 10, 10. $0.90/GB.
It can be found in the 840PRO, 850PRO, MX200, sm951, Intel 750, pretty much all enthusiast drives.
Again, faster reads and greater cell longevity but more expensive.
Finally you have TLC (triple) with 23 voltage states: 000, 001, 010, 011, 100, 101, 110, 111. $0.60/GB.
It's extremely cheap to manufacture and allows companies to get triple the capacity out of an equivalent SLC SSD.
It's TLC that brought affordable 1TB+ SSDs to the market, and it's even higher precision within a single cell that will likely bring us SSDs that compete with HDDs in terms of capacity.
However, at 19nm and below, cell volt degradation becomes a major issue.
The cells are so small that electrons can pretty much just float out of gates at whim (basically...), and it can easily pass the bit threshold where the SSD can efficiently read the cell state.
This is what the 840EVO suffered from: Any data that hadn't been touched for a long time had significantly reduced read speeds.
The first 840EVO 'fix' simply refreshed all voltages to where they should be... and then nothing, which is why users noticed performance problems reoccurring.
This second 840EVO 'fix', as I foresaw, just refreshes the voltages more frequently, effectively fixing the problem in lieu of somewhat reduced longevity.
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