The SSD Anthology: Understanding SSDs and New Drives from OCZ
by Anand Lal Shimpi on March 18, 2009 12:00 AM EST- Posted in
- Storage
Final Words
I began this article with a recap of my history with SSDs, stating that the more things change, the more they stay the same. Honestly, today, the SSD world isn't much different.
Drives are most definitely cheaper today; the Intel X25-M originally sold at close to $600 for 80GB and is now down in the $340 - $360 range. The Samsung SLC drives have lost their hefty price tags and are now just as affordable as the more mainstream MLC solutions.
But the segmentation of the SSD market still exists. There are good drives and there are bad ones.
Ultimately it all boils down to what you optimize for. On its desktop drives, Intel chose to optimize for the sort of random writes you’d find on a desktop. The X25-E is much more resilient to the workload a multi-user environment would throw at it, such as in a server and thus carries a handsome price tag.
At first glance it would appear that Samsung’s latest controller used in the preview OCZ Summit drive I tested optimizes for the opposite end of the spectrum: sacrificing latency for bandwidth. As the Summit was used more and more, its random write latency went up while its sequential write speed remained incredibly high. Based on these characteristics I’d venture that the Summit would be a great drive for a personal file server, while the Intel X25-M is better suited as a boot/app drive in your system.
I’d argue that Intel got it “right”. Given the limited sizes of SSDs today and the high cost per GB, no one in their right mind is using these drives for mass storage of large files - they’re using them as boot and application drives, that’s where they excel after all.
Over the past year Intel continually claimed that its expertise in making chipsets, microprocessors and generally with the system as a whole led to a superior SSD design. Based on my tests and my own personal use of the drive and literally every other one in this article, I’d tend to agree.
OCZ and Indilinx initially made the mistake of designing the Vertex and its Barefoot controller similarly to the Samsung based Summit. It boasted very high read/write speeds but at the expense of small file write latency. In the revised firmware, the one that led to the shipping version, OCZ went back to Indilinx and changed approaches. The drive now performs like a slower Intel drive; rightfully so, as it’s cheaper.
While I wouldn’t recommend any of the JMicron based drives, with the Vertex I do believe we have a true value alternative to the X25-M. The Intel drive is still the best, but it comes at a high cost. The Vertex can give you a similar experience, definitely one superior to even the fastest hard drives, but at a lower price. And I’ll spare you the obligatory reference to the current state of the global economy. The Samsung SLC drives have come down in price but they don't seem to age as gracefully as the Intel or OCZ Vertex drives. If you want price/performance, the Vertex appears to be the best option and if you want all-out performance, snag the Intel drive.
The only potential gotcha is that both OCZ and Indilinx are smaller companies than Intel. There’s a lot of validation that goes into these drives and making sure they work in every configuration. While the Vertex worked totally fine in the configurations I tested, that’s not to say that every last bug has been worked out. There are a couple of threads in OCZ’s own forums that suggest compatibility problems with particular configurations; while this hasn’t been my own experience, it’s worth looking into before you purchase the drive.
While personally I'm not put off by the gradual slowdown of SSDs, I can understand the hesitation. In the benchmarks we've looked at today, for the most part these drives perform better than the fastest hard drives even when the SSDs are well worn. But with support for TRIM hopefully arriving close to the release of Windows 7, it may be very tempting to wait. Given that the technology is still very new, the next few revisions to drives and controllers should hold tremendous improvements.
Drives will get better and although we're still looking at SSDs in their infancy, as a boot/application drive I still believe it's the single best upgrade you can do to your machine today. I've moved all of my testbeds to SSDs as well as my personal desktop. At least now we have two options to choose from: the X25-M and the Vertex.
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SunSetSupaNova - Wednesday, March 18, 2009 - link
Just wanted to say great job Anand on a great article, it took me a while to read it from start to finish but it was well worth it!FHDelux - Wednesday, March 18, 2009 - link
That was the best review i have read in a long time. I originally bought an OCZ Core drive when they first came out. It was the worst piece of garbage i had ever used. Newegg wouldn't let me send it back and OCZ support forums told me all sorts of junk to get me to fix it but it was just a poorly designed drive. I eventually ended up getting the egg to take it back for credit and i wrote OCZ off as a company blinded by the marketing department. I currently own an Intel SSD and its wonderfull, everytime i see OCZ statements saying their drive competes with the Intel drive i would laugh and think back to the OCZ techs telling me i need to update my bios, or i need to install vista service pack 1 before it would work right.I am thankful that you slapped that OCZ big wig around until they made a good product. All of us out there that wasted our time and money on Pre-vertex generation drives are greatfull to you and the whole industry should be kissing your butt right now.
One thing these companies need to learn is that marketing isn't the answer, creating solid products is. Hopefully OCZ has learned their lesson, and because of your article i will give them another chance.
THANK YOU!
kelstertx - Wednesday, March 18, 2009 - link
I didn't want to worry about eventual failure of the Flash chips of an SSD, and went with an SDRAM based Ramdrive from Acard. These drives have no latency of any kind, since they use SDRAM, and no lifespan of write cycles. I've been using mine for a couple of weeks now, and I like it a lot. I put Ubuntu on mine, and had 2G left for my small home folder. The standard HDD is my long-term storage for data files, music, etc. As SDRAM gets more affordable over time, I can add DIMMs and bump up the size.I know this review was about SSDs strictly, so an SDRAM drive doesn't technically fit, but it would have been interesting to see a 9010 or 9010b in there for comparison. It beat the Intel SSD in almost all the tests. http://techreport.com/articles.x/16255/1">http://techreport.com/articles.x/16255/1
7Enigma - Wednesday, March 18, 2009 - link
I've been eying these guys ever since the announced their first press release. Every time I always was drawn away by the constant need for power (4h max on battery scares the bejeezus out of me if I was to be gone on vacation during a storm), high power usage at all times, and high cost of entry (after factoring in all of the ram modules).I really dislike that article as well, since I think the bottlenecks were much less apparent with such a horribly slow cpu. The majority of that review's data is extremely compressed. I mean a P4, and 1 gig of memory; are you F'ing kidding me? This article was written in Jan of this year!? Why didn't they just use my old 486DX?
tirez321 - Wednesday, March 18, 2009 - link
What would a drive zeroing tool do to write performance, like if you used acronis privacy expert to zero only the "free space" regularly? Would it help write performance due to the drive not having to erase pages before writing?tirez321 - Wednesday, March 18, 2009 - link
I can kinda see that it wouldn't now.Because there would still be states there regardless.
But if you could inform the drive that it is deleted somehow, hmm.
strikeback03 - Wednesday, March 18, 2009 - link
The subjective experiences with stuttering are more important to me than most of the test numbers. Other tests I have found of the G.Skill Titan and similar have looked pretty good, but left out mention of stuttering in use.Too bad, as the 80GB Intel is too small and the ~$300 for a 120GB is about the most I am willing to pay. Maybe sometime this year the OCZ Vertex or similar will get there.
strikeback03 - Tuesday, March 24, 2009 - link
When I wrote that, the Newegg price for the 120GB Vertex was near $400. Now they have it for $339 with a $30 MIR. Now that's progress.kamikaz1k - Wednesday, March 18, 2009 - link
the latency times are switched...incase u wanted to kno.also, first post ^^ hallo!
GourdFreeMan - Wednesday, March 18, 2009 - link
It seems rather premature to assume the ATA TRIM command will significantly improve the SSD experience on the desktop. If you were to use TRIM to rewrite a nonempty physical block, you do not avoid the 2ms erase penalty when more data is written to that block later on and instead simply add the wear of another erase cycle. TRIM, then, is only useful for performance purposes when an entire 512 KiB physical block is free.A well designed operating system would have to keep track of both the physical and logical maps of used space on an SSD, and only issue TRIM when deletion of a logical cluster coincides with the freeing of an entire physical block. Issuing TRIMs at any other time would only hurt performance. This means the OS will have significantly fewer opportunities to issue TRIMs than you assume. Moreover, after significant usage the physical blocks will become fragmented and fewer and fewer TRIMs will be able to be issued.
TRIM works great as long as you only deal with large files, or batches of small files contiguously created and deleted with significant temporal locality. It would greatly aid SSDs in the "used" state Anand artificially creates in this article, but on a real system where months of web browsing, Windows updates and software installing/uninstalling have occurred the effect would be less striking.
TRIM could be mated with periodic internal (not filesystem) defragmentation to mitigate these issues, but that would significantly reduce the lifespan of the SSD...
It seems the real solution to the SSD performance problem would be to decrease the size of the physical block... ideally to 4 KiB, as that is the most common cluster size on modern filesystems. (This assumes, of course, that the erase, read and write latencies could be scaled down linearly.)