Any practical gains having a "2nd" SSD or Accelsior for scratch?

Discussion in 'Mac Pro' started by rawdawg, May 11, 2012.

  1. rawdawg macrumors 6502

    Jan 7, 2009
    OWC's Accelsior SSDs look awesome and I plan to get one for my system drive and applications whenever Apple decides to include us professionals with it's future plans (i.e. update it's Mac Pro).

    In the past we used scratch disks because HDDs were slow. Are current SSDs fast enough to operate both the system and scratch on the same drive? Or would there be an improvement having an additional SSD for scratch?
  2. ixodes macrumors 601


    Jan 11, 2012
    Pacific Coast, USA
    I have no personal experience using an SSD as you've described.

    What I do have is a Mac Pro with two 512MB Samsung 830 series SSD's. One I use for scratch, one as my primary drive. With this setup it's lightning fast and a real pleasure to use.
  3. jasonvp macrumors 6502a


    Jun 29, 2007
    Northern VA
    I always thought the quickest way to kill an SSD is to write to it a lot. TRIM enabled or not, they have a fixed number of writes and that number is a lot smaller than a physical drive (unless things have changed). Setting an SSD up as your scratch space is a good way to throw money away, IMHO.

    My solution: 2 10K RPM SATA drives RAID0'd together. If one of them fails, it's no big deal since it's just scratch space.

    And for what it's worth: I moved my swap file to that same volume as well, as opposed to leaving it on the SSD.

  4. derbothaus macrumors 601


    Jul 17, 2010
    So why use an SSD at all then? 4K writes are 80% of all computing use if you are booted from it. I don't operate so paranoid. They'll last long enough as to not worry about it.
  5. handheldgames, May 11, 2012
    Last edited: May 11, 2012

    handheldgames macrumors 68000


    Apr 4, 2009
    Pacific NW, USA
    Buy it and use it until it breaks. I personally would avoid long benchmarking sessions. :) And with the right adjustments, VM/Scratch can be placed onto another drive. On prior Win installations, I placed the OS on the 1st partition of one drive and scratch on the 1st partition of a second hard disk. Nothing went on the OS drive except the OS. Applications/desktop/documents/Users were even placed on their own partition. If the It kept the OS clean and happy until the users.dat slowdown would eventually kick on over time or a service pack upgrade would kill the installation. And if the OS did fail, a clean install could be completed without ever having to worry about overwriting personal data.
  6. Boomhowler macrumors 6502

    Feb 23, 2008
  7. Demigod Mac macrumors 6502a

    Apr 25, 2008
    In all likelihood you'll replace the SSD for a better one long before you run into any write limit problems.

    Wear-leveling tech also mitigates this problem.
  8. rawdawg thread starter macrumors 6502

    Jan 7, 2009
    I appreciate the replies and I agree not to worry about an SSD failing.. After having one 1.5 years as my system drive and scratch disk there have been no issues so this is not a concern.

    But seeing these Accelsior SSDs aren't cheap, and I'll spend my budget just buying the new MP, I was wondering if anyone thought given how dang fast they are if having a second as a dedicated scratch would improve speed in any order close to that of the reason we started using scratch disks in the first place.

    So, to specifically stay on topic for my question, do people who have SSDs for system drives doing photo and video work leave their scratch on their system drives?
  9. deconstruct60 macrumors 604

    Mar 10, 2009
    It is a space efficiency issue too. Pragmatically the Accelsior is just a SSD RAID set-up on a single PCI-e card. For those that may have put a SSD RAID set up inside of their box this consumes much less space since the "box" the conventionally packages SSD come in soak up room. The PCI-e just throws those boxes and SATA connectors away.

    Putting it on a card leaves 2-3 3.5" drives sleds open again for bulk storage. Or near-online storage (e.g. , a place to move projects/media before send it out of the box to archive/backup land. )

    Similarly, for the folks buying SATA re-routing kits to send the Mac Pro drive sled signals back to a 6Gbs SATA III RAID card .... skip diverting the "freeway" ... just buy a new one and stick it in the slot.

    Scratch and a OS/Apps/User are going to present different wear rates. It is going to be easier to track the wear indicators if they are separated. For example, may want to replace the scratch every 3 years while the OS/Apps/User drive goes the every 4-5. Both SSD and HDD are consumables. They wear out and if don't want to deal with "blows outs" you toss them proactively as they get close to point they are expected to have problems.
  10. rawdawg thread starter macrumors 6502

    Jan 7, 2009
    Thanks for responding and I appreciate the detailed explanation. Forgive me if this comes off wrong because I only I want to make sure my thread stays on topic, but those aren't the questions I was concerned about (and actually they were specifically the questions I asked not to respond about :D)

    My question is of the following two configurations, would one be notably faster than the other:

    Option 1.) A Accelsior SSD with BOTH system and scratch..... Or
    Option 2.) Two Accelsior SSDs, one with the system and one with a dedicated scratch.

    My apologies if this sounds....rude. Sometimes it seems you have to be pretty obnoxious to stay on topic :):p
  11. Mr Ski 73, May 20, 2012
    Last edited: May 20, 2012

    Mr Ski 73 macrumors regular

    Dec 11, 2007
    I am using one Accelsior as a boot drive and its very quick and better than my OWC Mercury I was using before. I am tempted to add a second 120GB but I am not sure if by striping this will be bootable.

    I think you will see a huge difference in write speeds (c1200MBPS) so long as its still bootable. at the minute I am getting 600+MBPS
  12. wonderspark macrumors 68040


    Feb 4, 2010
    My machine is built specifically for video editing, animation and photo work. I replaced my boot drive with a Crucial M4 256GB SSD and found that it didn't have any effect on video editing, but made boot-up and app launches a lot faster. It only takes up 95GB of space, since all my music and other storage-y stuff is located on a 4TB Hitachi 5K4000 HDD. That data is also backed up on another disk.

    I still use a dedicated HDD RAID-0 for scratch, and an external RAID-6 for working data and larger scratch / temp files. The internal RAID-0 does 215MB/sec and the external RAID-6 does 816MB/sec writes, 714MB/sec reads, so that's my fastest disk volume by far. This is all I need to edit / playback / scrub native DSLR footage without even rendering previews.

    I also have a little script that I copy/paste into Terminal that builds a 1.8GB RAM disk for scratch when I want better Photoshop performance. Since I have 32GB of RAM, this makes more sense than using an SSD for scratch.

    What I *do* use my second SSD for is a clone of my boot / OS disk. This way, if the boot SSD dies, I have another ready to drop in. I clone this SSD daily. I use my original 640GB boot HDD as a third clone that I don't update until major updates (like 10.6.7 to 10.6.8, or CS5 to CS5.5) are verified as good. This way, I can revert to an old boot in case an update manages to jack up my system.

    I noticed recently that I have twenty-one separate disks right now, and I can connect every single one of them to my Mac at once. That's amazing to me.
  13. laserbeam273 macrumors 6502

    Sep 7, 2010
    It's hard to say as those things are blazingly fast. With spinning drives and low level SSDs, I think the answer would be to keep them split, but I'm thinking that with the massive I/O rate they have just striping the two together will give you the best results. I think that the demand your system will have on the drive will pale in comparison to your scratch disk tasks (I'm assuming you're planning to buy them because you actually need them!), so it doesn't make sense dedicating half of your drives' throughput to it.

    Also the low latency of the drives again means less need for separation.

    Of course, if you really are trying to maximise your machines performance, try it one way for two weeks, then the other way for another two weeks, then let us know!
  14. Demigod Mac macrumors 6502a

    Apr 25, 2008
    I have an Accelsior and I can definitely say that it's had a noticeable effect in Photoshop, particularly in loading/saving large files and undo'ing stuff (this is coming from using a Mercury Extreme SSD, I imagine the difference will be enormous if you're used to traditional HDD speeds)

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