Fast external storage for new iMac

Discussion in 'Mac Accessories' started by bp1000, Sep 29, 2013.

  1. bp1000 macrumors 65816

    Jul 7, 2011
    With a new iMac on order i need to find a decent external storage option as i only opted for a 256GB SSD for my OS, apps and media cache / meta.

    I have been thinking of the Buffalo DDR for a while due to its good fit with my requirements and typical file sizes lower than 1GB.

    However i would like 2 drives. A 2TB and a 3TB Buffalo. But, can then both work at the same time as i understand OSX needs software to make use of the DDR cache.

    I need 2 because i would like 1 for my photo libraries, movies, music + other media which would be an attached storage device. The 3TB would be there as a time machine backing up the 2TB + 256 SSD.

    It would suck if 2x Buffalo DDR drives can't utilise the speed advantages at the same time. Does anyone know?

    The only other option i can think of is if i consider a good internal drive in a USB 3.0 enclosure. I heard these can achieve 200MB/Sec but not sure which drive or enclosure to go for.

  2. paulrbeers macrumors 68040

    Dec 17, 2009

    I'm confused, why even bother with this drive if you are going to store large files on it? With only 1GB worth of cache, you are going to quickly run out of cache and be reading and writing at direct HD speeds. That's the problem with all of these various drives with DDR or SSD caches, they aren't any better for large file storage than straight hard drive because you will quickly out run the cache. I read a couple of reviews and that's what they all said. Your image libraries are probably larger than 1GB as well as your movies and music playback wouldn't even phase a USB 2.0 drive. Same yourself the hassle and money and go straight hard drive. If you really need faster storage then you need to buy an external SSD drive...
  3. bp1000 thread starter macrumors 65816

    Jul 7, 2011
    I understand that transfers to writes over 1GB will revert back to normal write speeds for an average HDD.

    However i'd say 95% of my transfers to write are always under 1GB. If i ever wrote more than 1GB it might just be due to a video encoding which is CPU limited anyway.

    Any video encoding/export i do wont be able to deliver 200MB/Sec to the drive. An SSD would most likely have edge on seek / random access but then again not entirely suitable for storage. You could import and edit on an SSD but would still have to wait for offloading to a HDD, i would argue the offloading is longer than the import / export and time gained from faster in program performance.

    Random read access from these drives would be mediocre, that is my only concern. Surely if i was editing my masters from something like Aperture which stores masters on the 2TB DDR it would only require a transfer read speed in the tens not the hundreds of MBs. So theoretically i shouldn't notice any difference between SSD and HDD, apart from the initial access and probably batch jobs if the CPU and RAM weren't bottlenecking. But my previews and meta would be nicely served up on the internal SSD.

    I dont know how the DDR works but perhaps currently working files might store in DDR for read too.

    So surely DDR has advantages when working with Aperture masters, video writes etc. Surely it has an advantage as a working disk over a standard HDD in USB enclosure?

    I just hope that two can work together in DDR mode, 1 as time machine another as an attached storage device, backed up by TM.

    P.S. when they say USB 3.0 has a theoretical max transfer speed, is this per port or shared across all ports, in this example my iMac has 4.
  4. Macman45 macrumors G5


    Jul 29, 2011
    Somewhere Back In The Long Ago
    A little like the post above. If I wanted that kind of space AND speed to match, I'd look at a Thunderbolt RAID storage solution...Promise, WD etc. are all making them and the prices except for the very top of the range have started to fall.

    I've been using a Pegasus R4 with my iMac...I do store and work on large project files, but WD have cheaper solutions available that you might want to look at too.
  5. bp1000 thread starter macrumors 65816

    Jul 7, 2011
    This is the ultimate but in the realms of being a bit more than i wished to spend at the moment.

    The WD cheaper solutions; i did look at the WD II dual disk option, i wasn't sure what speeds i would achieve in raid 0 but i would still need another disk as a backup for the external storage and i believe it was still in the region of £250 - £300 when i looked which was quite pricey.
  6. g4cube macrumors 6502a

    Apr 22, 2003
    An external cache as in the Buffalo DDR external drive really cannot do any prefetch of information on the disk mechanism.

    The cache actually on the drive mechanisms are tied to the drive firmware, so that when an i/o request is made, the drive firmware can cache other nearby information from the disk surface (ie the same track on the disk and logically adjacent tracks). An external DDR Ram cache cannot do that as it has no information as to how info is stored on the disk.

    I think the DDR ram cache solution is great for making most benchmarks look good, but not too useful in most real-life use. Otherwise, we'd see the method mimicked by other manufacturers.

    Disclaimer: I do have the 2TB Buffalo drive, and it does NOT run circles around other drives. No real benefit for random I/O. Benefit only seen when reading/writing the same information over and over. The latter benefit can be seen with any drive that has god OS caching.
  7. paulrbeers macrumors 68040

    Dec 17, 2009
    While I don't have the Buffalo DDR drives, I do have a couple of the Seagate Hybrid drives with the 4GB of SSD Cache. Awhile back, I needed a fairly large External portable drive so I grabbed my 500GB Seagate Hybrid and assumed it would be faster than a standard mechanical. It was not. I would be great for things like an external OS drive, but for large file transfers it mattered none.

    I think you are 100% correct, it might be impressive in benchmarks, but not in real life usage. Frankly doing a little bit of research the only place it was at all impressive is for small less than 1GB transfers which is pretty pointless for a large external DATA drive.
  8. meistervu macrumors 65816

    Jul 24, 2008
    From what I read, Buffalo software is needed to turn on/off the cache. It's is not used for read/write.

    I am skeptical at the skeptics's claim that the 2 GB cache in the Buffalo DDR not helping in the real world performance.

    Sure, if all you do is copying large files between drives and the total size exceed the cache size, then logic dictates that there is no advantage.

    But that's not what most people use storage for. Say, you have an aperture library that is 1 TB in size. After a shoot you added 16 GB of photo files to it. The bottleneck of the initial copy is your memory reader and memory card, not the drive, so the Buffalo drive speed is not a factor because it's more than fast enough. But when the time comes to building the previews and indexing the library, I suspect the 2 GB cache in the Buffalo drive will make a difference. The cache only needs to be large enough to accommodate the I/O throughput of the task at hand.

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