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
I believe OCZ cut prices to distributors that day, but the retail prices will take time to fall. Once you see X25-M G2s in stock then I'd expect to see the Indilinx drives fall in price. Resellers won't give you a break unless they have to :)Take care,
Anand
bobjones32 - Monday, August 31, 2009 - link
Another great AnandTech article, thanks for the read.Just a head's-up on the 80GB X-25m Gen2 - A day before Newegg finally had them on sale, they bumped their price listing from $230 to $250. They sold at $250 for about 2 hours last Friday, went back out of stock until next week, and bumped the price again from $250 to $280.
So....plain supply vs. demand is driving the price of the G2 roughly $50 higher than it was listed at a week ago. I have a feeling that if you wait a week or two, or shop around a bit, you'll easily find them selling elsewhere for the $230 price they were originally going for.
AbRASiON - Monday, August 31, 2009 - link
Correct, Newegg has gouged the 80gb from 229 to 279 and the 160gb from 449 to 499 :(Stan Zaske - Monday, August 31, 2009 - link
Absolutely first rate article Anand and I thoroughly enjoyed reading it. Get some rest dude! LOLJaramin - Monday, August 31, 2009 - link
I'm wondering, if I were to use a low capacity SSD to install my OS on, but install my programs to a HDD for space reasons, just how much would that spoil the SSD advantage? All OS reads an writes would still be on the SSD, and the paging file would also be there. I'm very curious about the amount of degradation one would see relative to different use routines and apps.Anand Lal Shimpi - Monday, August 31, 2009 - link
Putting all of your apps (especially frequently used ones) off of your SSD would defeat the purpose of an SSD. You'd be missing out on the ultra-fast app launch times.Pick a good SSD and you won't have to worry too much about performance degradation. As long as you don't stick it into a database server :)
Take care,
Anand
swedishchef - Tuesday, September 1, 2009 - link
What if you just put your photoshop cache on a pair of Velociraptors? Would it be the same loss of benefit?I have the same question regarding uncompressed HD video work, where I need write speeds well over the Intel x25-m ( over 240Mb/s). My assumption would be that I could enjoy the fast IO and App. launch of an SSD and increase CPU performance with the SSD while keeping the files on a fast external or internal raid configuration.
Thank you again for a a brilliant Article Anand.
I have been waiting for it for a long time. Yours are the only calm words out on the net.
Grateful Geek /Also professional image creator.
creathir - Monday, August 31, 2009 - link
Great article Anand. I've been waiting for it...My only thoughts are, why can't Intel get their act together with the sequential business? Why can the others handle it, but they can't? To have such an awesome piece of hardware have such a nasty blemish is strange to me, especially on a Gen-2 product.
I suppose there is some technical reason as to why, but it needs to be addressed.
- Creathir
Anand Lal Shimpi - Monday, August 31, 2009 - link
If Intel would only let me do a deep dive on their controller I'd be able to tell you :) There's more I'd like to say but I can't yet unfortunately.Take care,
Anand
shotage - Monday, August 31, 2009 - link
Awesome article!I'm intrigued with the cap on the sequential reads that Intel has on the G2 drives as well. I always thought it was strange to see even on their first gen stuff.
I'm assuming that this cap might be in place to somehow ensure the excellent performance they are giving with random read/writes. All until TRIM finally shows up and you'll have to write up another full on review (which I eagerly await!).
I can't wait to see what 2010 brings to the table. What with the next version of SATA and TRIM just over the horizon, I could finally get the kind of performance out of my PC that I want!!