I'm planning to purchase a Crucial M4 256G SSD.

There are 2 versions though, 7mm and 9.5mm, at the same price on Newegg.com

My current laptop is 9.5mm SATA II. However, I plan to purchase a new laptop as soon as Ivy Bridge quad-core laptops (the 35W i7-3612QM interests me most) are available, which will certainly have SATA III (and I plan to use a legacy HDD in optical bay). However, I'm not sure if it will come with a 7mm or 9.5mm slot.

My question is, will a 7mm SSD fit in a 9.5 mm slot? Is there any disadvantage?

(BTW, comments are welcome if you feel Crucial M4 is not a good choice. I chose this after I read rumors about SandForce. I also do not see any reason to switch to Intel 320 Series as Crucial seems to have good reliability as well.)

  • 2
    Yes- as long as its not bigger. There is usally a caddy that holds the HDD. this is where the SSD will have to be put... so it will fit snug to specification, and usually when you put the cover on, the screws hold the caddy in place..
    – Piotr Kula
    Commented Jan 6, 2012 at 19:50
  • @ppumkin You mean 7mm will be able to fit into the 9.5mm slot just as if it is a 9.5mm one? I just viewed the photos on Newegg and it seems all screw's relative position to the connector are the same for both version.
    – Haozhun
    Commented Jan 6, 2012 at 19:54
  • Yea- its the thickness. It can be smaller than spec. But some 2.5" like 750GB are thicker and dont always fit.. The srews are positions absolutley to the sata port.. so that it will fir perfectly.. there is no need for convertors or anything. It is a standard that has to be follwed- or it will say- you need another caddy or something psecial- which is very rare. enjoy the ssd :)
    – Piotr Kula
    Commented Jan 6, 2012 at 19:57
  • 2
    @ppumkin Thank you for your answer. Why not answer my question, instead of commenting, so that I can accept your answer? :)
    – Haozhun
    Commented Jan 6, 2012 at 19:59
  • If your laptop does not have a caddy, you may need a shim to guarantee the drive doesn't move and put stress on the SATA connectors.
    – rob
    Commented Feb 8, 2014 at 3:44

3 Answers 3


enter image description here

Yes the 7.5mm, 9.0mm will fit into all 2.5" standard SATA bays, because the side screws will align the SATA port to the port on the motherboard. The same applies for thicker HDD's - but not all thicker ones will fill ie- wont be possible to screw the cover back on.

enter image description here

It is highly likley (only on some models of Acer do not use this) that there will be a caddy. You will need to put this on the SSD to maintain the correct alinement's and avoid damage to SATA port. enter image description here

Then the cover that goes over the HDD bay, will usually keep the cradle in place, stopping the drive from falling out of the connector.

XP Key courtosey of Google and some bloke who decided to publish it to Google Images.. All rights reserved..?

P.S.: Enjoy the SSD. I love the speed improvement, especially on loading apps and games. Amazing!

P.S.S: Recently I tried to fit a 9.0mm into a Dell netbook type thing. It did fit, just but the lid did not close and then I noticed the dell connector did not slot in. So please check in the manual to absolute sure that it will accept a 9.00mm

  • As long as it has a caddy, you're fine!
    – Shinrai
    Commented Jan 6, 2012 at 21:10
  • Note, my parents have a 1-year-old 17" Samsung laptop and it does not have a caddy. They would need a shim to guarantee the 7.5mm drive doesn't move and put stress on the SATA connectors.
    – rob
    Commented Feb 8, 2014 at 3:43

This is a good discussion - just one thing to add:

In Dell Precision laptops, I've found that the secondary drive bay works really well for BOTH the 7mm and 9.5mm drives but the primary drive bay doesn't. But, NEW Dell machines are shipping with a ~2mm rubber spacer.

So, why many systems do work - when the drive is screwed in (like in the secondard drive bays) it doesn't work as well in the primary. I had to create a shim (which I did out of some left-over "pluck and pull" foam from a Pelican case).

I wish the rubber spacers were easy to find though. I'd have bought one for sure!

hth, k


The connectors and screwholes are in the same place. So in most cases it's fine to fit a thinner driver in a laptop that is expecting a thicker drive.

However, some laptops support the drive in part through enclosing it in a space that is exactly the right size. Fitting a drive that is too thin without fitting some form of spacer can result in the drive not being mounted securely which could put stress on the connectors.

At least some SSDs come with a stick on spacer to avoid this problem. I don't know if the ones you are looking at do.

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