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Upgrade Advice: Does Your Fast SSD Really Need SATA 6Gb/s?

Benchmark Results: 4 KB Random Performance

As we noted in our 60/64 GB SSD round-up, we're changing the way we test using Iometer. In the past, we tested random transfers by benchmarking with four workers active in Iometer. This mimics threaded environment, as each worker represents a different application accessing the drive. However, that approach is also overoptimistic because four workers with one outstanding I/O operation each actually translates into a queue depth of four. In order to make things more realistic, we cut the number of workers to one, actually yielding a queue depth of one.

We made two additional tweaks to testing, better tuning the suite for our purposes here today. You see, the average desktop workload experiences a lot of bursty data transfers. However, our prior methodology emphasized sustained performance. In trying to reflect increasingly real-world results, our Iometer scripts now run for one and a half minutes. That's a substantial reduction from our previous scripts that ran for five minutes. Additionally, we're testing queue depths from 0 to 31 in increments of three, since SATA's Native Command Queuing extension only supports that many outstanding commands.

Random Read Performance

Examples include antivirus scans and typing in Word

At a queue depth of one, each SSD performs similarly on a 3 Gb/s or 6 Gb/s connection, except for the SandForce-based Vertex 3.

As you hit seven and sail past 10 outstanding commands, the 3 Gb/s standard constrains the entire field to the 200 MB/s.

Interestingly, Crucial's m4 is substantially slower than the competing 6 Gb/s-capable drives, though it does enjoy a performance boost attached to the faster interface.

For the other two drives (Samsung's 830 and OCZ's Vertex 3), SATA 6 Gb/s demonstrates its benefits at queue depths of four and higher. Once you hit seven outstanding commands, the interface allows these drives to deliver more throughput than a second-gen port would otherwise enable.

Random Write Performance

Examples include email, file compression, and Web browsing

As you can see in the chart below, Samsung's 830, Crucial's m4, and OCZ's Vertex 3 all lose a little bit of performance attached to a 3 Gb/s interface, even at a queue depth of one, accounting for a roughly 9% drop. That's despite the fact that all of these benchmark results fall well under what even a first-gen SATA interface can accommodate.

Although Intel's SSD 320 doesn't impress in this test, the gap between it and other SSDs becomes much wider once you move to a higher queue depth. For example, at more than 10 outstanding I/Os, the 240 GB Vertex 3 and 256 GB m4 top out around 180 MB/s plugged in to a 3 Gb/s port. That's roughly 70 MB/s faster than Intel's SSD 320, which hits its limit at 110 MB/s.

Once you switch to SATA 6Gb/s, the 240 GB Vertex 3 and 256 GB m4 accelerate significantly. At queue depths higher than four, both drives push past the 200 MB/s barrier easily.

  • compton
    Buying the best drive rather than the perceived fastest is good advice. I have fast drives and slow drives, but I prize the reliable ones. The good news is that there are drives which are both fast and reliable, so don't buy a drive just because of its Vantage score or simply because of the speed with which it handles 0-fill data.
    Reply
  • compton
    Which FW is the 830 using? The Test Setup and Benchmarks page lists it as CXM0. There are currently 3 FWs, CXM01,02,03]B1Q. The page simply lists CXM0.
    Reply
  • phamhlam
    Crucial m4, Samsung 830, and Intel 320 are all good drives. 128GB drives go for $180. They are the best value.

    I find it interesting that SATA 3 doesn't make a difference in file copy. Most SATA 3 drives cost the same as a SATA 2 so no need to save a few dollars.
    Reply
  • SteelCity1981
    So basiucly what this is saying is even thought SATA 3 looks impressive on paper, when it comes to actual real world results it's really not any faster than SATA 2 in performaning everyday real world task.
    Reply
  • dark_knight33
    I think I wrote you an email asking for this article when I was looking to buy my SSD a few weeks/months ago. Even though your article came after I purchased mine, thanks for addressing it. I'm rocking a Vertex III 240GB on my Sata II x58 MB and I don't regret it one bit.
    Reply
  • a4mula
    I can say this. I'm running 2x OCZ Solid first gen SSDs off SATA 3Gb/s ICH10R. When new they benched at about 300/100 sequential read/write. Compared to current generation drives this is pretty slow. When researching my current build I asked a friend that just put together a rig with a 64GB M4 on Intel 6Gb/s if I could give it a spin. While his machine boots faster w/o a doubt, I attest most of this to the RAID verification I face when I boot. Inside Win7 I couldn't tell a difference at all. While I'm sure his system is faster, it just wasn't obvious or noticeable in my opinion.
    Reply
  • sincreator
    What about quality? Is there any way to stress them till they start to fail? It just seems that if there isn't much difference in the drives in real world applications, then the next logical thing a buyer would want to know would be how much average data particuar drives can read/write before a failure. Like actual stress testing in a controlled environment. Come on Tom's, don't you want to destroy a few perfectly good SSD's? lol. These are things i would like to know more than anything else so I could make a very informed decision before a purchase.

    I asked before but no one answered. Anyway here goes... If SSD's are supposed to be more reliable than spinning drives, why are most warranties for 3 years instead of the usual 5 years on high end conventional spinning drives? It seems like the companies are not to confident in their products to me, and that's why I ask this question and the one that preceded it. It would be nice to get some honest answers......
    Reply
  • compton
    sincreatorWhat about quality? Is there any way to stress them till they start to fail? It just seems that if there isn't much difference in the drives in real world applications, then the next logical thing a buyer would want to know would be how much average data particuar drives can read/write before a failure. Like actual stress testing in a controlled environment. Come on Tom's, don't you want to destroy a few perfectly good SSD's? lol. These are things i would like to know more than anything else so I could make a very informed decision before a purchase. I asked before but no one answered. Anyway here goes... If SSD's are supposed to be more reliable than spinning drives, why are most warranties for 3 years instead of the usual 5 years on high end conventional spinning drives? It seems like the companies are not to confident in their products to me, and that's why I ask this question and the one that preceded it. It would be nice to get some honest answers......
    Well, the warranties are mostly 3 years, but some drives like Intel's 320s and Plextor's M3S drives do have 5 years of coverage.

    As for stress testing... well... some have taken this matter in their own hands to answer that very question. So far, it's far more than anyone could imagine. And for complex reasons, a drive only writing 10GB might not wear out it's NAND in over a century. A drive's endurance is typically way underestimated. No one is going to wear out any 3xnm or 2xnm NAND in 5 years, except in the most extreme cases. Most drives die from firmware problems, or physical damage to the PCB or components, or some other unknown phenomenon. Only the factory could do a proper autopsy, and since the FW, FTL, controller, etc. are usually trade secrets or covered under NDA, no one in the know is going to volunteer.

    There is an SSD endurance thread on the XtremeSystems forum:

    http://www.xtremesystems.org/forums/showthread.php?271063-SSD-Write-Endurance-25nm-Vs-34nm/page1
    Reply
  • heezdeadjim
    You probably aren't going to see much of a difference in speed while on the desktop from one SSD to another. It's when loading programs and game levels that you might see a real difference in.

    I know when I first got my 1st gen OCZ Vertex nearly when it first came out, I was always the first person on the map for Counter Strike. While other players were still loading the level, I would rush in from the side and lob a grenade and take a few people out because they didn't think anyone could get there so fast (now with more people with SSD's, it's not quite so funny anymore).

    I do appreciate being able to open PS CS5 in less than 2 seconds (for quick photo re-edits) and opening Premiere a lot faster too. Transferring large RAW photo folders (think 50+GBs total) to and from backup HDD's, I could use the extra MB's from these new 6Gb/s versions.
    Reply
  • cmcghee358
    I've read this article entirely too many times. Except this time it looks much better than the version I saw. Good job Mr. Angelini!
    Reply