The SSD Relapse: Understanding and Choosing the Best SSD
by Anand Lal Shimpi on August 30, 2009 12:00 AM EST- Posted in
- Storage
What's Wrong with Samsung?
The largest SSD maker in the world is Samsung. Samsung makes the drives offered by Apple in its entire MacBook/MacBook Pro lineup. Samsung makes the drives you get if you order a Lenovo X300. In fact, if you're buying any major OEM system with an SSD in it, Samsung makes that drive.
It's just too bad that those drives aren’t very good.
This is the 4KB random write performance of Samsung's latest SSD, based on the RBB controller:
4.4MB/s. That's 3x the speed of a VelociRaptor, but 1/3 the speed of a cheaper Indilinx drive.
Speedy, but not earth shattering. Now let's look at performance once every LBA has been written to. This is the worst case scenario performance we've been testing for the past year:
...and now we're down to mechanical hard drive speeds
Holycrapwtfbbq? Terrible.
Now to be fair to Samsung, this isn’t JMicron-terrible performance. It’s just not worth the money performance.
The Samsung RBB based SSDs are rebranded by at least two manufacturers: OCZ and Corsair.
The OCZ Summit and the Corsair P256 both use the Samsung RBB platform.
The Corsair and OCZ Samsung RBB drives.
The drive most OEMs are now shipping is an even older, lower performing Samsung SSD based on an older controller.
I talked to some of the vendors who ship Samsung RBB based SSDs and got some sales data. They simply can’t give these drives away. The Indilinx based drives outsell those based on the Samsung RBB controller by over 40:1. If end users are smart enough to choose Indilinx and Intel, why aren't companies like Apple and Lenovo?
Don't ever opt for the SSD upgrade from any of these OEMs if you've got the option of buying your own Indilinx or Intel drive and swapping it in there. If you don't know how, post in our forums; someone will help you out.
Samsung realized it had an issue with its used-state performance and was actually the first to introduce background garbage collection; official TRIM support will be coming later. Great right? Not exactly.
There’s currently no way for an end user to flash the firmware on any of these Samsung drives. To make matters worse, there’s no way for companies like OCZ or Corsair to upgrade the firmware on these drives either. If you want a new firmware on the drive, it has to go back to Samsung. I can’t even begin to point out how ridiculous this is.
If you’re lucky enough to get one of the Samsung drives with background garbage collection, then the performance drop I talked about above doesn’t really matter. How can you tell? Open up Device Manager, go to your SSD properties, then details, then select Hardware Ids from the dropdown. Your firmware version will be listed at the end of your hardware id string:
Version 1801Q doesn’t support BGC. Version 18C1Q (or later) does.
How can you ensure you get a model with the right firmware revision? Pick a religion and start praying, because that’s the best you can do.
Now the good news. When brand new, the Samsung drives actually boast competitive sequential write, sequential read and random write speeds.
These drives are also highly compatible and very well tested. For all of the major OEMs to use them they have to be. It’s their random write performance that’s most disappointing. TRIM support is coming later this year and it will help keep the drives performing fresh, but even then they are still slower than the Indilinx alternatives.
There’s no wiper tool and there’s currently no method to deploy end-user flashable firmware updates. Even with TRIM coming down the road, the Samsung drives just don’t make sense.
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Anand Lal Shimpi - Monday, August 31, 2009 - link
The tables the drive needs to operate are also stored in a small amount of flash on the drive. The start of the circular logic happens in firmware which points to the initial flash locations, which then tells the controller how to map LBAs to flash pages.Take care,
Anand
Bakkone - Monday, August 31, 2009 - link
Any gossip about the new SATA?Zaitsev - Monday, August 31, 2009 - link
Thanks for the great article, Anand! It's been quite entertaining thus far.cosmotic - Monday, August 31, 2009 - link
The page about sizes (GB, GiB, spare areas, etc) is very confusing. It sounds very much like you are confusing the 'missing' space when converting from GB to GiB with the space the drive is using for its spare area.Is it the case that the drive has 80GiB internally, uses 5.5GiB for spare, and reports it's size as 80GB to the OS leaving the OS to say 74.5GiB as usable?
Anand Lal Shimpi - Monday, August 31, 2009 - link
I tried to keep it simply by not introducing the Gibibyte but I see that I failed there :)You are correct, the drive has 80GiB internally, uses 5.5GiB for spare and reports that it has 156,301,488 sectors (or 74.5GiB) of user addressable space.
Take care,
Anand
sprockkets - Tuesday, September 1, 2009 - link
Weird. So what you are saying is, the drive has 80Gib capacity, but then reports it has 80GB to the OS, advertised as having an 80GB capacity, which the OS then says the capacity is 74.5GiB?sprockkets - Tuesday, September 1, 2009 - link
As a quick followup, this whole SI vs binary thing needs to be clarified using the proper terms, as people like Microsoft and others have been saying GB when it really is GiB (or was the GiB term invented later?)For those who want a quick way to convert:
http://converter.50webs.com">http://converter.50webs.com
ilkhan - Monday, August 31, 2009 - link
so they are artifically bringing the capacity down, because the drive has the full advertised capacity and is getting the "normal" real capacity. :argh:Vozer - Monday, August 31, 2009 - link
I tried looking for the answer, but haven't found it anywhere so here it is: There are 10 flash memory blocks on both Intel 160GB and 80GB X25-M G2, right? (and 20 blocks with the G1).So, is the 80GB version actually a 160GB with some bad blocks or do they actually produce two different kind of flash memory block to use on their drives?
Anand Lal Shimpi - Monday, August 31, 2009 - link
While I haven't cracked open the 80GB G2 I have here, I don't believe the drives are binned for capacity. The 80GB model should have 10 x 8GB NAND flash devices on it, while the 160GB model should have 10 x 16GB NAND flash devices.Take care,
Ananad