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Tycho 005917 · May 21, 2009, 06:44 PM

I recently bought a 1TB internal drive without properly researching the installation process on my iMac Core 2 Duo. I'm pretty uncomfortable doing the installation myself given the steps necessary on this computer, so I'm going to pick up an external enclosure for the drive.

Does anyone know roughly how much of a performance hit I'll see if I use the external as my boot drive as opposed to the internal? I'd really like it to be small enough not to notice, but I don't want to pay the fees to have a professional install the drive.

abbaZaba · May 21, 2009, 10:29 PM

I don't think you will notice much of a performance hit.

Simon · May 22, 2009, 02:26 AM

I would expect quite a performance hit. The SATA-USB bridge will bottleneck disk performance at probably around 30MB/s. That's way below what a 3.5" disk can deliver. If anything, you should look at getting a FW800 enclosure. They're more expensive and you'll still be limited by a bridge, but at least you should see something around 50 MB/s.

If I were you I'd take the Mac and the disk to an AASP and have them do the installation if you're not comfortable with doing it yourself. They will charge a fee, but you'll end up with a fast internal disk and no damage or hassle.

ghporter · May 22, 2009, 07:41 AM

SATA-to-USB, IDE-to-USB and "whatever"-to-Firewire bridges are ALWAYS going to be a bottleneck. They have to translate requests for data and pass them to the drive, then translate the drive's data and pass it through the link. That's a LOT of translation. While Firewire will generally be faster on a Mac (FW drivers tend to be better on Macs, USB drivers tend to be better with Windows), there's only so much that a fast link can do for you.

Simon's recommendation to have an Apple Authorized Service Provider install your new drive for you is a VERY GOOD ONE. This preserves your warranty, gets the job done fairly quickly, and gives you the end product you want: a fast-booting iMac with plenty of drive capacity. A local AASP charges about $50 to put a drive in a first-generation MacBook Pro; any aluminum iMac should be at most about the same price.