Very Slow SSD Speeds: Corsair Force GT

Discussion in 'MacBook Pro' started by macfan74318, Nov 28, 2011.

  1. macfan74318 macrumors member

    Aug 9, 2011

    I just installed my Corsair Force GT (60 GB) drive and the speeds are horrible. I am getting 88 write and 330 read which is much slower than the advertised speed. Any advice? Also TRIM is enabled on this drive.

  2. Satnam1989 macrumors 65816

    Nov 16, 2011
    Did u enable trim? or is it enabled on its own? I got a Corsair Force Series 3 180GB.....not the GT but its a SATAIII I'm only getting read/write of 189/180.....far below 550/520ish advertised....i used blackmagic app from Mac App Store to test.....I don't have any extra settings enabled like file vault 2 or anything, but its what it is...
  3. macfan74318 thread starter macrumors member

    Aug 9, 2011
  4. HellDiverUK macrumors 6502

    Oct 24, 2009
    Belfast, UK
    330MB/s is excellent. What are you complaining about?!?

    A normal drive will be doing 60-80MB/s read and 30MB/s write if you're very lucky.
  5. thundersteele macrumors 68030

    Oct 19, 2011
    It's not so great if the manufacturer promises 550 MB/s read and probably 300-400 MB/s write speeds.

    My sata II apple ssd has about 180-190 write and 210 read, but I just ran the benchmark once or twice.
  6. jlc1978 macrumors 68020


    Aug 14, 2009
    Those are probably burst speeds and you're test is giving you sustained speeds which will be much lower typically.
  7. macfan74318 thread starter macrumors member

    Aug 9, 2011
  8. dusk007 macrumors 68040


    Dec 5, 2009
    I assume you are testing with compressed data. Force GT is sandforce thus it won't do as well with incompressible data such as random data.

    When I compare it to anandtech data of ASSD benches it looks to be right.
    Write perfromance is 160/170 on the 120GB version. Half the space usually means also half the writing speed.
    Read speed sounds reasonable too.
    What many people don't seem to understand is that for good performance 120GB is the minimum. The smaller the process the less nand chips and the higher you need to go with capacity if you want to get all the benefits of an 8-10 channel interleaved controller.
    256GB still performs much better than 120GB. Going up to 512 is not really necessary. 60GB still offers good enough read speeds but for writing you'd be better off with an HDD at least sequentially.
    120GB doubles write performance and gets you full speed reads 256GB would increase write performance again but not as much as 120GB already populates all channels afaik, 256GB just interleaves request and can achieve some more performance through that.
    Sandforce drive manufactures cheat with the specifications as they can reach those top speeds but only with very well compressible data. Fortunately much system data is compressible for a system drive it isn't that bad of a choice.

    HellDriveUK doesn't seem to know what he is talking about. HDDs usually are qually fast in writing and reading and do so sequentially upto 110MB/s current gen 2.5". And normal SSD aren't that slow either.

    PS: Compare drive speeds here.
    There is only the Force GT 120GB in the database but you can just compare the Agility 3 which is there in many sizes to see what size difference does to performance in each benchmarks.
  9. altecXP macrumors 65816

    Aug 3, 2009
    If anyone is interested I have a 120GB Force 3 and a 240GB Hyper X that I might be getting rid of shortly now that I moved to an Air.

    If you are interested just PM me.
  10. macfan74318 thread starter macrumors member

    Aug 9, 2011
  11. dusk007 macrumors 68040


    Dec 5, 2009
    No it is not but it is not as fast a you thought. Mostly in rar extracting situations that matter but in most other cases (starting apps, loading data ..) the read speeds matter and they are fast enough. You wouldn't feel the difference to 500MB/s in responsiveness.
    Also with system data it is actually faster in reality than what this incompressible bench makes it look like.
    Also don't forget than random speeds are still good. This is where HDDs really suck. With 0.5 to 1.5 MB/s in read/write random data and your SSD probably still yields some 50MB/s random read and probably much more than 80MB/s random write as those are quite often compressible.
    Also the latency of 16ms form HDDs is now some 0.05 ms. Which is quite a lot faster.

    It sucks if you often extract rars, traballs and stuff. If you often write big files to the drive that are compressed like movies, mp3, jpeg. In that case you should have spent the money for a bigger drive and possible one that isn't Sandforce. More importantly a bigger drive though.

    Just for reading and as a system drive it will be more than good enough with those speeds.
    It is still much faster than the mSATA Intel 310 SSDs which they intend to use for the SRT feature in Ivy Bridge.
  12. macfan74318 thread starter macrumors member

    Aug 9, 2011

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