After replacing HDD cable, low disk speeds

[jamesjingyi]

Hi all,

After replacing my hard drive cable, my MacBook Pro has been getting disk read speeds of about 120mb/s. Installed is a Samsung 840 Pro SSD. However it seems to get about 440mb/s write. Is this a fault? I am pretty sure before I replaced the cable I was getting a lot higher speeds. I am wondering whether it is a fault with the cable or whether Blackmagic Disk Speed Test is just giving me bad results. Is there another way to check?

Thanks

James

 

[Brian Y]

Hi all,

After replacing my hard drive cable, my MacBook Pro has been getting disk read speeds of about 120mb/s. Installed is a Samsung 840 Pro SSD. However it seems to get about 440mb/s write. Is this a fault? I am pretty sure before I replaced the cable I was getting a lot higher speeds. I am wondering whether it is a fault with the cable or whether Blackmagic Disk Speed Test is just giving me bad results. Is there another way to check?

Thanks

James

First of all, why did you replace the cable? The original issue might be key.

It could be the disk dying - what kind of speeds do you get if you just copy a large file in Finder?

 

[maflynn]

What happens when you put the older cable back?

 

[jamesjingyi]

First of all, why did you replace the cable? The original issue might be key.

It could be the disk dying - what kind of speeds do you get if you just copy a large file in Finder?

I replaced it because it did not show up in the computer at all and would not boot (? Folder).

After replacing the thing worked again

The drive is fine as everything works well and I can boot from other computers using an external hard drive caddy

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What happens when you put the older cable back?

Nothing, the old cable is completely dead

 

[KUguardgrl13]

I have no idea if this is the case or if it's even possible, but maybe you installed a SATA II cable instead of a SATA III? I know that older Macs that are limited to SATA II can't get the speeds that most SSDs specify.

 

[AlexMaximus]

shield it..

The only thing that comes to mind it to shield the cable.
The original is a very flat non shielded cable. OWC once offered a shielding kit to wrap the cable for faster speeds and less errors for the MBP 17'
According to IEEE specs, a shielded cable can transmit more data and chances of error is significant less. Thats what I did. Its experimental, but it "felt faster" since then.
The kit is not available any more, however check youtube for shielding cables.

 

[maflynn]

Nothing, the old cable is completely dead

Pick up another cable then, but I wonder if its some other hardware failure.

 

[jamesjingyi]

OK, thanks for your help everyone, I'm gonna try and get this fixed asap!