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High Queue Depth Sequential Performance

OCZ RevoDrive Hybrid: Solid-State Speed With Hard Drive Capacity
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Application-level testing represents the performance you would see from these five configurations in everyday desktop use. But it doesn't really help us determine if OCZ's write-back caching strategy is any better than the write-through default Intel recommends for Smart Response Technology.

This drive needs to live up to its RevoDrive namesake, which is why we're turning to ATTO and maxing out queue depth. If you're shopping for a PCI Express-based SSD, it's because you need the sort of throughput not available from a conventional 6 Gb/s SATA drive, and you have the workloads able to push data rates that high with a number of outstanding requests.  

Bear in mind that the graph above applies to data living on the RevoDrive Hybrid's flash. Because ATTO tops out at 2 GB of LBA space, it operates completely within this drive's NAND memory. Naturally, that's only representative of a best-case scenario, where you're reading information that has already been cached.

In such an environment, the benefits of the RevoDrive Hybrid are clear, and OCZ's mixed-media offering delivers performance similar to what you'd get from a RevoDrive 3. In sequential reads, it's actually possible to achieve more than 1 GB/s if you're moving large bits of data at high queue depths. Sequential writes aren't as impressive. But again, so long as you're operating exclusively on data within that 100 GB cache, you're going to realize great performance, outpacing any other caching solution.

So, what happens when you start reading or writing data that isn't already cached? After all, this product boasts 1 TB of capacity, only one-tenth of which fits in flash. Once you fill that space and have to start ejecting data from the cache and writing it to disk, performance drops off precipitously.

In an attempt to demonstrate what happens, we turn to Iometer and set an LBA range of 200 GB. There, sequential writes are seen to drop as low as 55 MB/s. That's the less-glamorous figure we come up with when information must be evicted from cache and then written to disk.

How about when you need to read data on the hard drive, before it's actually cached? Iometer logs indicate that Toshiba's 5400 RPM drive gives you something closer to 70-80 MB/s. Obviously, that's hardly ideal. But it's what you have to expect before data is cached.

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  • 3 Hide
    aznshinobi , October 24, 2011 4:49 AM
    This should be compared with the Seagate Momentus XT, where's that?
  • 2 Hide
    LuckyDucky7 , October 24, 2011 5:11 AM
    Except for those who don't have SATA 6GB/s controllers on their motherboards, this product is a little redundant.

    I mean, it's really cool and all, but since Vertex 3 drives on their own run about 200 bucks for 120GB, you could get 2 x OCZ Vertex 3's in RAID, and a high-performance 1TB 7200 RPM drive like the Western Digital Caviar Black (the one mounted there is 5400RPM) for the same price as this drive.

    So instead of the rather limited 120GB, you'd get 240GB of SSD storage instead, along with a faster hard drive. Because with 240GB, who needs cache?
  • -9 Hide
    chumly , October 24, 2011 5:24 AM
    What a dumb idea.
  • -8 Hide
    zybch , October 24, 2011 5:39 AM
    LuckyDucky7Except for those who don't have SATA 6GB/s controllers on their motherboards, this product is a little redundant.I mean, it's really cool and all, but since Vertex 3 drives on their own run about 200 bucks for 120GB, you could get 2 x OCZ Vertex 3's in RAID, and a high-performance 1TB 7200 RPM drive like the Western Digital Caviar Black (the one mounted there is 5400RPM) for the same price as this drive.So instead of the rather limited 120GB, you'd get 240GB of SSD storage instead, along with a faster hard drive. Because with 240GB, who needs cache?

    Yeah, like i want to use 'scary'RAID in my system. Screw that.
  • -1 Hide
    alidan , October 24, 2011 6:38 AM
    zybchYeah, like i want to use 'scary'RAID in my system. Screw that.


    than i believe use a raid 5, i think thats it, raid the 2 ssds and get another hdd in there as a backup for the two ssds
  • 3 Hide
    rantoc , October 24, 2011 8:40 AM
    alidanthan i believe use a raid 5, i think thats it, raid the 2 ssds and get another hdd in there as a backup for the two ssds


    For a raid 5 at least 3 drives is needed. And the chipset integrated raid5 solutions don't have powerful checksum offloading either meaning its either slow or hogs the cpu. Sure raid 5 is awesome in its ways but it also has its drawbacks.
  • 3 Hide
    billybobser , October 24, 2011 8:55 AM
    Just raid 0 and actively backup important files yourself if you can't take the drawbacks of it.

    If something just created is really worth saving, save it twice. Else just a back up image per week.
  • 0 Hide
    shqtth , October 24, 2011 10:32 AM
    This should be compared with the Seagate Momentus XT, where's that?
    ..

    It should be !


    Also why use 5400rpm? why not 7200rpm? Or use the XT.


    To me, this product looks like its hurting. Overpriced.


    I tested a few of the XT's are they are quick. Pretty much constant 100+ data and super low latency on common tasks.
  • 0 Hide
    Reynod , October 24, 2011 11:13 AM
    Could you please look at a direct comparison with the Momentus XT please?

    I have one as well.

    From what I can see this is a bit better than the XT but it would be good to know Andrew.

    Cheers !
  • 1 Hide
    nebun , October 24, 2011 12:17 PM
    zybchYeah, like i want to use 'scary'RAID in my system. Screw that.

    download the correct drivers and set it up correctly and you will have no issues....i have been using raid 0 for over 5 years with no issues at all
  • -2 Hide
    jacobdrj , October 24, 2011 1:09 PM
    shqtthThis should be compared with the Seagate Momentus XT, where's that? ..It should be !Also why use 5400rpm? why not 7200rpm? Or use the XT.To me, this product looks like its hurting. Overpriced.I tested a few of the XT's are they are quick. Pretty much constant 100+ data and super low latency on common tasks.


    Heat, for one, reliability for another, vibration (on a PCIe slot, no less) yet another...
  • 0 Hide
    SIR-Blade , October 24, 2011 1:56 PM
    For those that dismiss the "cache" scenario out of hand, i.e. could buy a 2TB HDD and a stand alone SSD, they miss the whole point. Caching takes the "work" out of deciding the data that you want in the SSD. The more you use the app/data, the more likely most of it will be in cache, and you only have to work with a single drive letter.

    The other scenario that You could use from OCZ, is do what I've done. Use their synapse drive as the cache, with a 5 *1TB RAID 1+0 on an Gigabyte X58 Mboard, i.e. no Z68 option available.
    So I get the security/speed of a RAID array, and quick load times for OS and my favourite games, when cached. (The synapse is via the SATA III channel.)
    For the ultimate, scenario, just add another 60GB SSD for those choice games/apps for those that absolutely positively had to be loaded ASAP.
    Simples.
  • 1 Hide
    SIR-Blade , October 24, 2011 1:58 PM
    The momentus is for a totally different target. It only has 4Gb NAND, so it would be like comparing apples with pears.
  • 2 Hide
    jacobdrj , October 24, 2011 2:09 PM
    SIR-BladeThe momentus is for a totally different target. It only has 4Gb NAND, so it would be like comparing apples with pears.

    Yes, and no...

    It is still a hybrid solution. At least we could see what the differences are, and therefore, we can decide which market we fall in: Either Momentus or Revo Hybrid...

    Personally, I think the Momentus would be on par, for most applications, with the RevoH if they would include closer to 24 GB of NAND, and therefore, this comparison would be much much closer...
  • 0 Hide
    cyberkuberiah , October 24, 2011 2:14 PM
    not confusing at all :) 
  • 0 Hide
    SIR-Blade , October 24, 2011 2:17 PM
    But the SSD is PCIe based, whereas the Seagate is SATA II if memory serves me correctly. The point of the Revo drive is to beat the SATTA II and III bottle neck, and provide large HDD capacity as well.

    And then the big difference ... the size of the cache ... 4GB for the Seagate ... 100Gb for the Revo .. actually (114Gb .. 14% over provisioned)
  • 1 Hide
    CaedenV , October 24, 2011 3:57 PM
    This is going to be one of those fun "remember when" articles. Remember when people were so desperate for performance and space that they had to attempt this Frankenstein of a device?
    Truly I do not see the market for the device. It limits the capability of a truly fine SSD, with a slow laptop drive attached to it. You would get much better performance raiding a few SSDs in 0, 1, or 10, and putting your active project on that drive. If your drive was too large to fit on the SSD portion in the first place then you would see little to no benefit at all. Then, put a real HDD in as your cold storage device. Much less messy, little bit cheaper, and better/consistent performance. Not to mention all those extra writes that are supposedly going to destroy the SSD portion of this drive anyways.
    Like I said, a few years from now when we are completely on SSD we will really laugh at these devices.
  • 1 Hide
    CaedenV , October 24, 2011 4:02 PM
    *if your PROJECT is too big to fit on the ssd... doh!
  • 1 Hide
    agnickolov , October 24, 2011 5:28 PM
    Honestly, the price should be almost halved - ~$200 for the SSD part and ~$60 for the HDD part comes to $260 for the package, which is slightly more than half of $500. Certainly shouldn't exceed $300.

    Relating to the Seagate Momentus XT comments: I wish Seagate had released a sensible flash composition - 32GB flash for a 500GB or 1TB drive would have been perfect IMO. Such a drive would have had much better commercial success. With only 4GB, all I'm thinking is - why bother...
  • 0 Hide
    wendellowen , October 24, 2011 5:36 PM
    It would have been nice to have seen a couple of 1TB drives in Raid 0 in this shootout. I, along with a fairly large portion of my friends have been doing this for years. I should add that all of us have NAS boxes (they are super cheap now, even running in RAID 1) for valuable file/photos. Hell, I think youu can buy 4 1TB drives and a NAS box for less than a 240GB SSD.
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