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SATA 3gb/s vs. 1.5gb/sec - backward compat?

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July 17, 2010 9:05:56 PM

Hi,

I want to update my 160gb drive in my 2008 MacBook (White version). It shipped w/ a Travelstar 5K250 that is listed at 1.5gb/sec for transfer rate.

The drives I'm looking, e.g., WD7500BPVT, WD Scorpio 750gb, has a spec of 3gb/sec.

Are the newer drives backward compatible, such that, it will dial down the transfer rate to the interface I have?

Or do I have to get a drive that lists both transfer speeds of 3gb/sec and 1.5/gb, e.g, the Toshiba MK7559GSXP 750gb drive.

Many thanks in advance.

a c 415 G Storage
July 17, 2010 9:15:31 PM

The drives with the faster SATA connections are compatible with slower SATA ports.

The mechanical platters don't spin fast enough to actually transfer data faster than 1.5Gbit/sec anyway, so don't feel like you're hurting the drive's performance by connecting it to a 1.5Gbit/sec port - you're not.
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July 17, 2010 10:19:56 PM

thanks for the info. makes shopping for a replacement that much easier.
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July 18, 2010 5:39:15 PM

i have done just that a couple of days ago .
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a c 342 G Storage
July 19, 2010 4:54:59 AM

SATA devices are supposed to be backwards compatible, so what you ask - connect a SATA I (3 Gb/s) HDD to an original SAT (1.5 Gb/s port) should work. The SATA II drive is supposed to automatically slow down its communication rate.

HOWEVER, there are times when it does NOT work, and the automatic adjustment fails. For this situation many HDD makers provide a way to force their SATA II drives to slow down to 1.5 Gb/s. Seagate and WD and a few others do it by installing a jumper on pins on the drive's back edge. NOTE that, although this looks a bit like the older Master and Slave adjustment system on IDE drives, it is NOT: jumpers on SATA drives are for other purposes entirely. So, if you need to make this jumper change, don't play with any others.

Some HDD makers have a different way to do this - I know of one that uses a software utility to set a register on the HDD. You best guide is to go to your HDD maker's website and check their instructions for how to force your HDD (identify by model no.) to go slow IF you need to do it.
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July 20, 2010 1:09:40 AM

Sure enough, after I was assured by Western Digital that the drive would step down, I went ahead and installed it my computer.

Nope, it isn't recognized. There is a compatibility issue w/ the Scorpio and the intel ICH8-M AHCI SATA controller in my MacBook 2008, version 3,1. :fou: 

Any chance someone has tried something simliar? What is the largest capacity 9.5mm drive someone has installed in a MacBook w/ the intel ICH8-M AHCI SATA controller?

Many thanks.
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July 20, 2010 1:10:35 AM

cyberkuberiah said:
i have done just that a couple of days ago .


What did yo do a couple of days ago? Install a larger capacity hard drive in a MacBook? If so, what drive did you use?

Many thanks.
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a c 415 G Storage
July 20, 2010 2:02:25 AM

nycjdc said:
Nope, it isn't recognized. There is a compatibility issue w/ the Scorpio and the intel ICH8-M AHCI SATA controller in my MacBook 2008, version 3,1. :fou: 
Check out Paperdoc's post - the drive may have a jumper you can set to force it to connect at the slower speed.

I'm the furthest thing from a Mac guru you're likely to see around here, but I'm also wondering if your problem may merely be a formatting issue. Brand new disks on Windows PCs won't show up in the file viewer until they've been partitioned and formatted - is there any possibility that's what's preventing you from seeing your drive when it's attached to the Mac?
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July 20, 2010 2:17:03 AM

sminlal said:
Check out Paperdoc's post - the drive may have a jumper you can set to force it to connect at the slower speed.

I'm the furthest thing from a Mac guru you're likely to see around here, but I'm also wondering if your problem may merely be a formatting issue. Brand new disks on Windows PCs won't show up in the file viewer until they've been partitioned and formatted - is there any possibility that's what's preventing you from seeing your drive when it's attached to the Mac?


Sorry, I should have said that on this 2.5" WD drive there are only four pins, none of which control transfer rate; they only control speed spin up/down and some other burst thing. The tech guy at WD told me that it should auto-select down.

But I wonder whether you are on to something about formatting. I put back the original HD in the MacBook, installed the WD 750gb drive in an external enclosure and it is seen by Mac OS and i can format it; but that is presumably because of the controller in the external hard drive enclosure.

I just found another user who has used this exact WD drive in this exact model MacBook and he was able to get it to fly by using a 3rd party utility called SuperDuper - a cloning utility. (I'm trying that now; not too keen on cloning the drive - don't know if that will cause any issues down the track; rather do a fresh install). I guess after cloning I can reinstall the new WD drive in the MacBook and see if it boots, if so, could do a fresh install?

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a c 342 G Storage
July 20, 2010 2:24:15 PM

Yes, I looked closely at the WD website since you said that's the brand you have, and was surprised to see that on PORTABLE HDD's their pin and jumper system does NOT have a pin pair to force SATA 1.5 Gb/s. But I also was thinking as sminlal - maybe you have to Partition and Format to be able to "see" the drive. I don't know enough about Mac's to know how you came to the conclusion that your system was not recognizing the new HDD.

Now, your original plan was to replace the older 160 GB HDD with a new 750 GB unit. The long clean way is to install the new HDD, Install your OS on it, then install and configure all your applications on it, then connect the old HDD and copy all user data files to the new drive, creating folders for them in the process.

The quick and easy way is to clone the old HDD to the new one. The clone process does three critical things. It Partitions and Formats the new HDD unit to create a "drive" that will hold the copied data, and should mark the Partition Table to indicate that this is the boot partition. Then it copies the OS to the new drive, ensuring that all critical system files are placed where they can be found for boot purposes. Then it copies absolutely everything else so that your clone is a COMPLETE and bootable copy of the original and can completely take over as the boot device.

I'm not a Mac user, but here's something to watch for from a PC user's experience. In making the clone, the software first creates and Formats a Primary Partition on the new HDD unit. Such software makes its own assumptions for a default size of the new Partition. Some do NOT presume you want to use the entire HDD as one huge volume and will offer to make the new Partition less that that. If that is what you want, and you plan to create a separate second Partition to be used as another "drive", you're OK. But many users want the entire HDD space to be the C: drive. So at the very beginning of the process you need to watch what the cloning software says it is doing and, if necessary, intervene manually through menus to set the Partition size as you want it.
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July 20, 2010 11:24:44 PM

Got It! :bounce: 


So, as I mentioned, I was not able to boot of the install DVD and lay down a partition table and format the WD7500BPVT. This was because the WD Scorpio drive was not recognized. I surmise this was because, by default, the WD drive is set up to be a Windows hard drive. And I guess the Mac OS 10.x can't recognize the disc.

So through the utility SuperDuper, which clones a drive, I reinstalled the original 160gb drive, booted off it, and cloned my 160 gb dirve to the WD 750gb drive, which was connected via a firewire connection to an external enclosure.

Then I pulled my 160gb drive out of the Macbook, installed the 750gb drive and pressed the power button. Normally the computer will boot up w/in 30 seconds. After cloning it would take approximately 150 seconds - 5x as long. This kinda smelled to me.

So now that I could boot the computer off the larger WD drive, I simply reinstalled the OS and now it boots fine, i.e., in about 30 seconds. Have no idea why via cloning it took so long to boot.

In the end, it appears like the source of the problem was partition/formatting the drive. Thanks to all for your help. I know have 10,000+ music tracks on an internal drive on my Macbook rather than an external. ;) 
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a c 342 G Storage
July 21, 2010 8:25:40 PM

Success! Hooray!
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!