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Replace Hard Drive with SSD

System Info: MacBook Pro running OS X 10.9, mid 2009, 13", PN MB991LL/A (2.53 GHz), 8GB RAM


I started having some problems with my system, mainly slow downs, especially when using Safari. I got a copy of Scannerz (http://scsc-online.com/Scannerz.html) and it confirmed drive platter damage. I know some of these units are supposed to have cable problems but Scannerz tested that too and found no problems with the cable, so this is a bonafide drive problem (it's 6 years old, you know).


I'd like to go ahead and replace it with an SSD and have some questions:


  1. Maybe I'm getting models mixed up but I seem to remember something about a drive thermal sensor on Apples not being compatible with generic drives. I know I read that somewhere I just don't remember where?
  2. I assume, if #1 above isn't a problem, that I can basically use any SATA SSD. Now I know I should get the fastest interface possible, but are there any caveats or incompatibilities that some brands of SSDs may present?
  3. What about stuff like trim and wear leveling. WIll this be in a driver for the SSD or does the OS take care of it automatically?
  4. Are there any brands/models to stay away from?
  5. Should I replace the cable too? I've heard they can get bad.


Thanks in advance.

MacBook Pro, OS X Mavericks (10.9.5)

Posted on Apr 4, 2015 12:06 PM

Reply
212 replies

Apr 4, 2015 6:22 PM in response to HuntsMan75

#1 was associated with the iMac as MrJavaDeveloper says.


#2 OWC is a good place to start, as spudnuty says, and this is worth a look-see.


#3 Wear leveling is one of the many activities which is part of "Garbage Collection" that's built into every SSD's controller in order to compensate for the differences in operation between hard disks and SSD's. TRIM is a service that the computer's OS provides to the SSD controller to again compensate for HD/SSD differences and is useful to the SSD's operation. However, it is only activated by default for Apple SSD's. It can be activated with third party utilities for third party SSD's but such activation does not play well at all if you're using or plan to upgrade to Yosemite. See this explanation.


#4 I don't know of any brands to avoid but in your research you might look into how easy it is to update firmware. Some are way harder than others.


#5 If you're careful, the cable should survive the swap. Note that OWC offers videos on SSD installation.

Apr 4, 2015 9:24 PM in response to HuntsMan75

HuntsMan 75,

I replaced my hard drive with a SSD from MacSales, also known as OWC. It is designed to take care of garbage collection, has it's own TRIM built-in, and is completely compatible with my MacBook Pro Early 2011.

The largest one in the Pro grade is 480 G and the largest in standard is 1T.


They are very easy to install and OWC has the instructions on-line to include a video.


I'm running 10.10.2 and very happy with the speed.

Apr 5, 2015 2:56 PM in response to Kevin41269

Kevin41269 wrote:


This article in ZDNET explains it better than I can...

Thanks, but I already know what TRIM is (I find this article to be more comprehensive and to the point).


In a nutshell, TRIM helps to compensate for the differences between hard disks and SSD's and how a computer's OS relates to them. One such difference is that while a HD can simply write to a space that contained a file which has been deleted, an SSD controller must first erase that space. Moreover, while a deleted file may have occupied one page on an SSD, the SSD controller can only erase a whole block of pages, and some of those pages may contain valid data. To avoid erasing valid data, any page that is still valid must first be moved elsewhere. However, while the OS knows about the deleted file, the SSD controller doesn't, and the result is that the deleted file's page(s) get moved too. TRIM is the mechanism that's used to keep the SSD controller apprised of deletions so that those pages don't get moved and thus can be erased. Running with TRIM normally off (as in Yosemite) prevents that notification from taking place, so when the controller's Garbage Collection routine starts running, it has no way of knowing that the page with the deleted file can be erased without first moving its contents.


Things get more complicated with the SandForce controller in OWC's SSD's. One of the tricks in the SandForce controller's bag of tricks is file compression on the fly when possible. So the LBA that the OS refers to when the notification via TRIM that the file has been deleted is passed to the SSD controller may be different from the page(s) of the actual file on the SSD. Moreover, SandForce also appears to use data deduplication as part of the compression process so some files become more important than others, something the OS knows nothing about. This article gives a more detailed explanation of SandForce and TRIM.


BTW, as you mention, the largest standard OWC SSD is 1TB. I've been using the earlier version of that, the OWC Mercury Electra 3G MAX SSD, for over two years without a hiccup. That one doesn't support TRIM because OSX identifies its Medium Type as Rotational in System Information. And that's because it's actually two 480GB SSD's stacked in one case and tied together in a RAID configuration, which, you'll see in the Wikipedia article, doesn't support TRIM.

Apr 6, 2015 10:58 AM in response to FatMac-MacPro

First, thank you to everyone that responded. Now I have some questions on TRIM:


1. If TRIM isn't enabled, will the lack of it be noticeable performance wise?

2. If I got a drive that's the same model as one in Apple systems, would TRIM be enabled, or is there something customized in the firmware that states the SSD is allowable as an Apple TRIM candidate.


Thanks again.

Apr 6, 2015 11:15 AM in response to HuntsMan75

Probably the best demonstration of TRIM's benefit can be found here, especially by examining the graph.


TRIM support of Apple's SSD's is based on the OS identifying the SSD as being from Apple, presumably by examining its firmware. So getting the same model as Apple's but without Apple's firmware would still present the third party conflict. The one exception which managed to bridge that gap is discussed in this article and its embedded links. Note that it also deals with SandForce controllers and TRIM.

Apr 7, 2015 11:01 AM in response to HuntsMan75

I have to throw a monkey wrench into the "SSD love fest" but they aren't perfect. If you get one, make sure you use a regular hard drive to do backups on it. I know of two people that have had SSDs go bad on them. In one case one of the memory chips was marginal and it kept dropping memory cells until the guy replaced it. On another the thing just lost all of its contents in a split second for no apparent reason, but the SSD was apparently not damaged. This was all within the last six months too, and the drives weren't some obscure brand made back in the days of yore, they were new. The one that blew all its contents was an Intel. I don't remember the other one, but it was a common, well respected brand.


Treat an SSD like it's a permanent mega-cache that you need to backup. I have a sneaky feeling as time passes and more people start using them you'll hear more and more about this sort of thing.

Apr 8, 2015 6:31 PM in response to ThomasB2010

If you read the linked report it states they subjected the SSDs and HDDs to something on the order of 3000 faults. I don't know about you but my power doesn't go out that often.😁


A better measure or conclusion would have been to indicate the probability of a failure like that occurring on a given unit when subjected to an average number of faults that one might realistically expect to experience during the lifetime of a unit. It is good, however, to see that the hard drives held up.

Apr 8, 2015 10:04 PM in response to spudnuty

OK I'm answering myself because I want to address everyone.

So addressing failure rates:

There is a sudden failure due to power interruption for SSDs. Apparently only the Intel doesn't have this problem. However the operational advantages of an SSD are such a game changer that you gotta go with them. That's why Apple used them in the Airs.

If you read through Googles report on the failure rates of all their conventional drives the failures are spread, time wise, across the board. Subsequent discussion referred to the drives becoming cheaper and cheaper. Ergo the failures come earlier and more frequent.

Replace Hard Drive with SSD

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