Samsung 840 Pro 256gb SSD - Amazing

Discussion in 'Mac Accessories' started by Tom Sawyer, Apr 11, 2013.

  1. Tom Sawyer macrumors 6502a

    Tom Sawyer

    Joined:
    Aug 29, 2007
    #1
    All I can say is WOW! If anyone is shopping for a new SSD I would highly recommend the 840 Pro.

    This is installed in a 2011 2.5ghz Mac Mini
     

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  2. passey macrumors member

    Joined:
    Mar 28, 2013
    #2
    best upgrade you can do to a mac.

    I'm running the 250 840 from usb 3.0 on my imac and getting 450 read / 250 write
     
  3. Tom Sawyer thread starter macrumors 6502a

    Tom Sawyer

    Joined:
    Aug 29, 2007
    #3
    No doubt... I've used SSD's for quite a few years now back to the original Intel drives and nothing compares. To see a single drive pretty much max out a sata 3 bus is pretty amazing.
     
  4. garybUK Guest

    garybUK

    Joined:
    Jun 3, 2002
    #4
    I bought the 250gb 840 (non-pro) and have had to RMA them x3 times already in less than a month. Horribly unreliable, hopefully the Pro version is better.

    When they are working they are fantastically quick and great value for money.
     
  5. kapalua12 macrumors 6502

    Joined:
    Jun 20, 2010
    Location:
    United States
    #5
    Those are great speeds. One SSD will not max out the speed of a SATA III bus though. You would need several drives in Raid 0 all running off SATA III headers to achieve anywhere near the maximum speed of a SATA III bus. Motherboards don't have enough SATA III headers to Raid 0 enough SSDs to max out the bus speed.
     
  6. itickings macrumors 6502a

    itickings

    Joined:
    Apr 14, 2007
    #6
    Picking the pro over the non-pro should be a no-brainer.

    Your failure rate sounds a bit high. I would guess that either all drives were from a single defective batch or something in your system is triggering the problems.

    I think you are overestimating the capabilities of SATA III, did you get bits and bytes mixed up? 600MB/s isn't all that much compared to a modern SSD...
     
  7. Tom Sawyer thread starter macrumors 6502a

    Tom Sawyer

    Joined:
    Aug 29, 2007
    #7
    By the specs, 6 gbit/sec roughly translates to 600 mb/sec... so it's pretty close... I suppose you would get the same speed per port so two in a Raid 0 should give 1.2 gb/sec (in theory, probably would be slower in reality). Still pretty amazing that a single drive can get this kind of speed.

    No issues with the drive here so far.... it's been rock solid.
     
  8. kapalua12 macrumors 6502

    Joined:
    Jun 20, 2010
    Location:
    United States
    #8
    They are great drives. Yes, speeds of two in raid zero are less than 2 times one drive alone, but they still do not saturate a SATA III bus at least with my Vertex 3 MAX IOPS SSD drives in Raid 0 off Intel headers (slightly older technology).
    But they do definitely show the benefit of Raid 0 over single drives. 4 SSD raid 0 set up is incredibly fast.

    I'll try and find a picture of the drives ATTO performance for different file sizes.
     
  9. Giuly, Apr 23, 2013
    Last edited: Apr 23, 2013

    Giuly macrumors 68040

    Giuly

    #9
    6GBit/s with an 8b/10b encoding - or 6*8/10 = 4.8GBit/s = 600MByte/s.
    Most of the SSDs are advertised as 'Up to 540MB/s', though, and that seems as good as it gets for SATA-III.
     
  10. kapalua12 macrumors 6502

    Joined:
    Jun 20, 2010
    Location:
    United States
    #10
    two OCZ max iops ssds will push the sata controller to it's limit on the high end approx 1.1GB/s.
    i have two gaming machines running raid 0 volumes from Vertex 3 max ssds and they are quick!
     
  11. itickings macrumors 6502a

    itickings

    Joined:
    Apr 14, 2007
    #11
    What is this "SATA III bus" thing you keep talking about? Can you provide a definition and any relevant numbers?

    Unless you actually need the raw transfer rate, striping the drives actually will lower the performance since the access will be slightly slower...

    I'm obviously not a gamer, but I have a hard time imagining that the increase in raw transfer rate by striping two fast SSDs enhances performance enough to compensate for slightly increased latency. A single fast SSD is quite fast nowadays.
     
  12. kapalua12 macrumors 6502

    Joined:
    Jun 20, 2010
    Location:
    United States
    #12

    Latency of SSD's is negligible. Two times negligible is still negligible. Striping 2 SSD's is done all the time to increase read/write speeds. Thus the LaCie Thunderbolt 1 TB Thunderbolt Little Big Disk's reason for being. Fast file transfers for video editing, or anything you want blazing speed for. Imagine if LaCie had actually put 2 Samsung 840 Pros in their Raid drives or 2 Vertex 4's in them.
     
  13. itickings macrumors 6502a

    itickings

    Joined:
    Apr 14, 2007
    #13
    For the record - striping introduces overhead, resulting in added latency that is not necessarily proportional to the drives' latencies...

    Paraphrasing: two times fast is still fast. ;)

    Most of the time consumers run SSD in striped configurations just to brag about numbers even though there are no real-life gains whatsoever. Reads/writes can often be small enough to make the practical difference between 500MB/s and 1000MB/s negligible. Spending money for a combo of a negligible gain paired with a negligible loss for the sake of bragging is not my cup of tea.

    Yes, there are workloads where the throughput is needed. I am perfectly aware of that. In fact, that's exactly why I wrote "Unless you actually need the raw transfer rate" (which you conveniently left out when quoting). The part you did quote was me being curious about the benefits of striped SSDs for gaming... Recording gameplay video might of course be one possible use case, but other than that I'm drawing a blank.

    Any news about your "SATA III bus" by the way?
     

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