The SSD Relapse: Understanding and Choosing the Best SSD
by Anand Lal Shimpi on August 30, 2009 12:00 AM EST- Posted in
- Storage
Impact of Idle Garbage Collection
The other option that Indilinx provides its users to improve used performance is something called idle or background garbage collection. The idea is that without any effort on your or the OS’ part your drive, while idle, will defragment itself.
The feature was actually first introduced by Samsung for its RBB based drives, but I’ll get to the issues with Samsung’s drives momentarily.
It either works by looking at the data on the drive and organizing it into a less fragmented state, or by looking at the file system on the drive and attempting to TRIM based on what it finds. Both Indilinx and Samsung have attempted to implement this sort of idle garbage collection and it appears they do it in different ways. While the end result is the same, how they get there determines the usefulness of this feature.
In the first scenario, this is not simply TRIMing the contents of the drive, the drive doesn’t know what to TRIM; it must still keep track of all data. Instead, the drive is re-organizing its data to maximize performance.
The second scenario requires a compatible file system (allegedly NTFS for the Samsung drives) and then the data is actually TRIMed as it would be with the TRIM instruction.
Details are slim, but the idle garbage collection does work in improving performance:
| PCMark Vantage HDD Score | New | "Used" | After TRIM/Idle GC | % of New Perf |
| Corsair P256 (Samsung MLC) | 26607 | 18786 | 24317 | 91% |
Presumably this isn’t without some impact to battery life in a notebook. Furthermore, it’s impossible to tell what impact this has on the lifespan of the drive. If a drive is simply reorganizing data on the fly into a better (higher performing) state, that’s a lot of reads and writes when you’re doing nothing at all. And unfortunately, there’s no way to switch it off.
While Indilinx is following in Samsung's footsteps with enabling idle garbage collection, I believe it's a mistake. Personally, real TRIM support (or at least the wiper tool) is the way to go and it sounds like we’ll be getting it for most if not all of these SSDs in the next couple of months. Idle garbage collection worries me.
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Anand Lal Shimpi - Monday, August 31, 2009 - link
Intel insists it's not an artificial cap and I tend to believe the source that fed me that information.That being said, if it's not an artificial cap it's either:
1) Designed that way and can't be changed without a new controller
2) A bug and can be fixed with firmware
3) A bug and can't be fixed without a new controller
Or some combination of those items. We'll see :)
Take care,
Anand
Adul - Monday, August 31, 2009 - link
Another fine article anand :). Keep up the good work.CurseTheSky - Monday, August 31, 2009 - link
This is absolutely the best article I've read in a very long time - not just from Anandtech - from anywhere.I've been collecting information and comparing benchmarks / testimonials for over a month, trying to help myself decide between Intel, Indilinx, and Samsung-based drives. While it was easy to see that one of the three trails the pack, it was difficult to decide if the Intel G2 or Indilinx drives were the best bang for the buck.
This article made it all apparent: The Intel G2 drives have better random read / write performance, but worse sequential write performance. Regardless, both drives are perfectly acceptable for every day use, and the real world difference would be hardly noticeable. Now if only the Intel drives would come back in stock, close to MSRP.
Thank you for taking the time to write the article.
deputc26 - Monday, August 31, 2009 - link
been waiting months for this one.therealnickdanger - Monday, August 31, 2009 - link
Ditto! Thanks Anand! Now the big question... Intel G2 or Vertex Turbo? :) It's nice to have options!Hank Scorpion - Monday, August 31, 2009 - link
Anand,YOU ARE A LEGEND!!! go and get some good sleep, thanks for answering and allaying my fears... i appreciate all your hard work!!!!
256GB OCZ Vertex is on the top of my list as soon as a validated Windows 7 TRIM firmware that doesnt need any work by me is organized....
once a firmware is organised then my new machine is born.... MUHAHAHAHAHAHA
AbRASiON - Monday, August 31, 2009 - link
Vertex Turbo is a complete rip off, Anand clearly held back saying it from offending the guy at OCZ.Now the other OCZ models however, could be a different story.
MikeZZZZ - Monday, August 31, 2009 - link
I too love my Vertex. Running these things in RAID0 will blow your mind. I'm just waiting for some affordable enterprise-class drives for our servers.Mike
http://solidstatedrivehome.com">http://solidstatedrivehome.com
JPS - Monday, August 31, 2009 - link
I loved the first draft of the Anthology and this is a great follow-up. I have been running a Vertex in workstation and laptop for months know and continue to be amazed at the difference when I boot up a comparable system still running standard HDDs.gigahertz20 - Monday, August 31, 2009 - link
Another great article from Anand, now where can I get my Intel X-25M G2 :)