Internal Macbook Pro HD Extremely Slow but External USB HD Works Great

I know this is an old thread, but did the new cable fix your problem? I am working on a MacBook Pro for a friend with exactly the same symptoms. Thinking the original drive was bad, I swapped it out for an SSD that I had on hand. Turns out to have exactly the same problem. I can put the original drive in an external dock and it boots normally. I can also boot from a flash drive quick as can be. But if I put the drive back in the computer, it takes forever to boot and is virtually unusable once it's finally started up. Also thought perhaps it was bad RAM, but I removed each of the two 2GB modules and booted from each and results were the same. (Since it booted normally from an external drive, I was pretty sure the RAM was fine, but it was easy to test.) Also ran both a quick and extended Apple Hardware Test (boot with option-D) and those came back clean. That's when I finally gave up and searched Google and ended up here. 🙂

So because it's not my computer, I don't want to just start throwing parts at it. If this cable fixed your problem, then I'll at least recommend it. I'm not going to get into replacing a motherboard, but the cable would be cheap and easy. Thanks in advance for any info about your results!

kmarkwardt,

you could try switching the disks — put the external one inside, put the internal one outside, and try booting from the now-external disk. If the originally internal one works well externally, and the originally external one works impossibly slowly internally, then that would point to your internal SATA cable being faulty.

kmarkwardt,

if the disk inside of your external enclosure has a form factor bigger than 2.5 inch, 9.5 mm high, or if it isn’t readily removable from its enclosure, then yes, it wouldn’t fit internally. If that’s the case, then I’d start with purchasing a replacement internal SATA cable, and seeing if replacing that makes a difference.

kmarkwardt,

I’ve seen recommendations in other discussions here about a particular eBay seller of these cables — if you hunt around, you’ll probably find reference to it. Another source for the cables is iFixit — I think that they sell both new and used ones.

I put a Samsung 840 PRO SSD into my Mid 2010 MacBook Pro, and for me, yes, it cracks to be sufficiently up. 😉 I’ve read here that the most recent firmware version of the Samsung 840 EVO SSD has resolved previous problems on Macs, and that the Crucial SSDs are recommended by several people. SSD-wise, I only have experience with the 840 PRO, so that’s the extent of my own recommendations.

If your near an Apple store make a Genius bar appointment and have them test the machine.....it's free for the exam.

If the cable from the HDD to the mother board is bad then they will replace it for around $56. The part is around $17 and labor is $39, or you can buy from EBay or iFixit and install it yourself (if that's the problem). I'd let Apple do it if that's the problem.

As far as SSD's, if you've never used a computer with SSD you will be pleasantly suprised with the major boost in speed and increase in battery life. You can expect boot times from between 15 to seconds, and apps open almost instantly.

I would highly recommend Crucial for your new SSD, I've had nothing but good luck with there drives. The Crucial M500 480GB SSD for around $230 and the NEW Crucial M550 512GB SSD for around $320.

The Samsung SSD's are only slightly faster than the Crucial SSD (were talking milliseconds), however from what I've read the Crucial SSD is more Mac friendly and also more reliable. When it's comes to data storage I want the highest reliable SSD, not necessarily the fastest.

I have a Crucial M4 256GB in a Mid-2009 MacBook Pro (M4 is nearly 2 years old) and Crucial M550 512GB in a Mid-2012 Macbook Pro (2 months). The M4 was in the 2012 MBP until I purchased the M550.

kmarkwardt wrote:

Unfortunately I'm about an hour and a half from the nearest Apple store. I just ordered the replacement cable, and will just do it myself.

I realize reliability is paramount in a Drive, but what about the Seagate drives and others I'm seeing on Amazon. http://www.amazon.com/Seagate-Solid-Hybrid-2-5-Inch-ST1000LM014/dp/B00B99JUBQ/re f=sr_1_4?ie=UTF8&qid=1399573096&sr=8-4&keywords=6.0gbps+ssd

Reviews are good, and it appears compatible. Am I asking for trouble?

No, I don't believe your asking for trouble with what you've picked out. Good reviews are always important.

Don't buy a drive until you figure out your current problem. Hybrid drives are a good choice for speed when needing a large amount of storage and you have a limited budget.

Just to let you know that adding a SSD's to your computer will be the biggest upgrade your computer will ever see....it's literally like buying a new computer (from the future).

Depending on the "link speed of your computer"

Link Speed: 6 Gigabit

Negotiated Link Speed: 6 Gigabit

You can check this by going to "About this Mac" clicking on "SATA/SATA Express".

If the Link Speed is 6GB and the Negotiated Link Speed (NLS) is 6GB then your computer has the fastest Link Speed.

A rotary HDD will on give you NLS of 3GB where as a modern SSD will be at 6GB

Although the drive you picked out does indicate the NLS is 6GB

FWIW, a new cable fixed the problem I described above (under the wrong account). 🙂

Hello Brent.

I have similar problem here. You can read it here if you have time Macbook SSD Very very Slow on Mac, Perfect on Windows

I really want to understand why my mac os is working terible while my windows was perfect in same cable if really it is a cable problem ?

do you have any idea?

are you sure that I have to replace my cable?

thanks