I have a Samsung 830 SSD in my notebook connected to a SATA interface. This is a rather old HP notebook nc8430 which means SATA is SATA I and not II or even III that disk supports. But SATA I still supports speeds up to 150MB/s so I expected at least double values as per image below.

CrystalDiskMark shows rather slow performance:


I've been using this SSD for over a year now and I would like to know what to do to make it blazingly fast as other reports say it should be?


As suggested I'm adding AS SSD screenshot of the test.


And Samsung Magician's benchmark which is likely biased...

Samsung Magician

  • run AS SSD Benchmark (alex-is.de/PHP/fusion/downloads.php?download_id=9) and post some pictures. – magicandre1981 May 23 '14 at 17:17
  • @magicandre1981: I added the requested. It seems this disk is really really slow. – Robert Koritnik May 26 '14 at 18:27
  • ok,the correct drivers are used and the alignment is ok. So 118MB seams to be the max for SATA1. – magicandre1981 May 26 '14 at 18:30
  • @magicandre1981: Max for SATA1 is 1.5Gb/s = 192MB/s. Ok theoretical. Practical should be above 150-ish... What about writes taht should be just the same as declared write speed is 400+MB/s, so it should saturate my SATA1 as well? And more alarming are rates for 4k which are straight appalling? – Robert Koritnik May 27 '14 at 8:57
  • maybe your controller doesn't support features like NCQ which also makes it slower. – magicandre1981 May 27 '14 at 17:27

Samsung Magician does the trick

I've run Samsung Magician and in indeed it improved the situation quite drastically. It ran SSD optimization as well as optimized OS for speed (disabling some services) and here are the same tests as above but with quite different results. Especially the 4k performance and access times are now enormously improved. Samsung Magician apparently has a suitable name. :)

I've also added the over provisioning option although haven't tested without it.


as AS SSD's results show similar increase in performance.


  • the values are only a bit higher compared to the original values. I see no real improvement by those "tweaks" – magicandre1981 May 27 '14 at 17:26
  • 30 times faster on 4k and 45 times faster access time is just a bit for you? That's a lot to me. – Robert Koritnik May 28 '14 at 9:51

Seeing that your SSD has 34% harddrive space left, is it possible you have filled your SSD to a point where it was lower than 25% free space?

SSD drives are different from normal HDD drives in regards of how it stores data. Whenever data is written to the SSD it will do so to empty clusters first. But it might not fill all sectors of a cluster. So per cluster there will be empty sectors. When a file is removed, it will use TRIM to mark clusters that are completely empty as new free space. This is how an SSD gets its speed.

If your space goes lower than 25% free, it is usually the point where there are no free clusters anymore. So files will be written to sectors on existing clusters, which means the files become fragmented. Due to this, when a file is removed, the cluster is usually not completely empty, and thus cannot be marked as free. Since accessing files over multiple clusters slows down access considerably, this is where the slowdown comes from.

To make your drive fast again, you first need to ensure you are having at least 25% free diskspace, and will keep having enough space, then find a defragger tool specificly for SSD's (normal tools won't recognise the different clusters, so make sure it is capable of working with SSD's) to reorganise the drive. This will make your drive fast again, and should only be performed once, then avoid having your space go below 25%.

Alternatively, you can try freeing/moving as much files off the SSD as possible, and then move them back, but this will not ensure that the speed comes back as some of the files that remain may still be fragmented.

  • 34% is usage percentage. I'm using 81GB of 238GB available which is approx 34%... So there's 66% free space on my SSD. – Robert Koritnik May 23 '14 at 12:36
  • Ah my bad, you're right. Still performance should be much better, but it will degrade if you get your harddrive filled too much. – LPChip May 23 '14 at 20:42

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