Resolved 750GB 7200RPM vs. 500GB Momentus XT

Discussion in 'Buying Tips and Advice' started by dlimes13, Jun 22, 2011.

  1. dlimes13, Jun 22, 2011
    Last edited: Dec 25, 2011

    dlimes13 macrumors 6502a


    May 3, 2011
    Perrysburg, OH
    Just got rid of my Seagate 500GB Momentus XT drive and replaced it w/ a 750GB 7200RPM Seagate. How big of a performance hit will I be taking?

    Model #'s:
    500GB: ST95005620AS
    750GB: ST9750420AS

    I figure it shouldn't be much, since I don't use the same programs and applications over and over again. I am back and forth between many programs and Boot Camp. Didn't take any $$ hit, as I sold the XT for the cost of the 750GB, but I just want to know what it'll be like (I'm so used to SSD's on other computers, I forgot what a regular hard drive was like). Thank you!
  2. r0k macrumors 68040


    Mar 3, 2008
    I use the Momentus XT and I love it. I replaced a 160 GB 5400 RPM drive that came with my early 2008 white Macbook. I know 7200 RPM helps but the 4GB hybrid SSD helps even more. My boot time, while faster than any PC I've ever owned, improved by more than half when I switched to the Momentus XT. In fact I'm seeing boot times that rival pure SSD. The drive figures out what you use. It's entirely transparent. It's using the same technique that is used for cache.

    The Momentus XT comes with 32 MB of Cache (RAM), 4 GB of SSD and 500 GB 7200 rpm HDD storage. The SSD is only used for reads not writes. When you fetch data, it checks RAM first, then SSD, then HDD. Whatever it reads gets copied to RAM and SSD during the fetch so if you come back a few hours later looking for the same stuff... it's already loaded.

    This means that data left sitting in SSD, like the boot files for OS X or your address book or gets loaded blindingly fast. If you are transcoding video, of course you'll wipe out the 4GB SSD with data that isn't "frequently used" but no big deal. Within a couple of days the SSD will be overwritten again with stuff you need every day.

    Now that you have dumped the XT, you will see slower boot times. I'm not sure by how much. Also there is no longer a 4GB "buffer" between you and the HDD. Only cache. I'm sure it will be better than anything I saw with my dusty old 5400 RPM drive but it will be noticeably slower than the Momentus XT.

    The real question is what are you seeing now that you have made the switch? Does it bother you or not?

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