Good Read on SSD's and TRIM and Garbage Collection (GC)

Found this post on another forum by Kent Smith who is "Sr. Director of Marketing and Performance Analysis for the division at LSI (soon to be owned by Avago) that makes the SandForce Flash controllers."

TRIM vs. Garbage Collection: Beating a dead horse - SSD - Storage

Very informative.

 

Great read.

 

Okay read, but keep in mind that it is still SF biased. TRIM doesn't work properly in any SF drive I know of. Duracrap, er, I mean Durawrite is also overblown; it simply throttles the drive's write behavior without removing that throttling when it can (or should). It simply takes away performance that the user paid for (usually without the user actually ever having used it). AND; it needs SE to restore that performance (for the next ten minutes of the drives use...).


See:
AnandTech | The Full Intel SSD 525 Review: 30GB, 60GB, 120GB, 180GB & 240GB Tested - Print View

Clean After Torture (30 mins) After TRIM
Intel SSD 525 240GB 293.5 MB/s 59.8 MB/s 153.3 MB/s


Yeah; below HDD levels, even on an Intel SSD.

Notice that for an O/S drive, a SF based SSD works fine (especially with OP'ing, contrary to what that post suggests) - almost any other use will give you an expensive device that an M4 (256GB or larger) can run circles around in that same usage scenario.


As usual; informative is relative. You always need to ask who's saying it and why...


It does point out that filling an SSD with data defeats all the algorithms an SSD has for staying healthy (GC and TRIM subroutines).

It also indicates correctly that TRIM is not an SSD's sole responsibility; the O/S is what needs to initiate it. When the SSD actively acts on that information that the O/S provided is what separates SSD's from each other. An either/or approach doesn't work in many usage scenarios - GC and TRIM needs to happen both during idle (background) and during use (active/foreground) of the SSD in question. This is why OP'ing works: it lets the active/foreground GC/TRIM to happen at maximum speed (and least WA) even when the user is sitting there looking at the system waiting for it to finish the requested task.


Where real world experience flies in the face of that post is where it states that TRIM is equivalent to extra OP'ing. Haven't seen that yet.

Even on drives that were only 20% filled (with my typical usage scenario) but using the whole formatted drive (Intel 520 Series, SanDisk Extreme, Crucial M4, etc.).


Nothing (new) was shown that having unallocated space (~30% or more), plus free space for the O/S and Programs as needed (~25GB - 175GB in my case), along with an O/S that can leverage an SSD (like Win8.1 can) fully with TRIM support is still not the way to the fastest, sustained, over time, performance from an SSD you can get.

But yeah; it was a good read while I munched my toast this morning.

 

That post was describing how TRIM works and GC in general, with some examples for Sandforce and other controllers, not Sandforce specific. What you said was basically what he said...

 

Not everyone uses a SSD to store tons of MP3s and HD videos. A lot of users simply want their OS to feel fast. Not everyone can afford a 960GB SSD. Heck, from a general statistic of this forum, most want it to improve loading speeds in video games and boot up times. Why would anyone purchase a 960GB SSD to store MP3s? Are you really going to listen to over 900 GB of music?

This guy who probably has his google calendar filled with colored boxes from early morning to midnight decided to give people an insight into how things work and instead you would berate him? May be a lesson in humility is in order?

WingNut, this was a good find. :thumbsup:

 

I do not doubt how busy and well intentioned he might be. I am not berating him either.

I am suggesting that he is looking out for himself and/or the company he works for; nothing wrong with that by itself.

What I am also suggesting is that everyone else who reads it do so with their best intentions in mind: the two are not always aligned.