iMac G5 Hard Drive Upgrade--Jumper settings?

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iMac G5 Hard Drive Upgrade--Jumper settings?

Hi. This is a pretty technical question, and Apple tech support could not answer my question over the phone. I'm hoping someone on this forum can help out.

My iMac G5 20" 1.8 GHz was mfd. in Jan. 2005. It has a 160 GB SATA drive from Seagate (via Apple). This is a model 7200.7 Barracuda. It has jumpers on two pins, but I don't know why. On the Seagate (non-Apple) 150 GBps drives, Seagate says that no jumpers are necessary, so I don't quite understand this.. but that's not my question.

The logic board has been replaced, which presumably also replaced the SATA controller.

I am replacing the drive with a Seagate 7200.11 Barracuda 320 GB drive, which is capable of 300 GBps interface. According to the Seagate web site, I need to install a jumper on this new drive *only if* the SATA controller on my iMac G5 is incapable of handling the 300 GBps interface.

Does anyone know if this speed-limiting jumper setting is required for my iMac using a 300 GBps SATA drive?

Thank you.

iMac G5 20" 1.8 GHz, 2GB, 160GB, Mac OS X (10.4.11), mfd Jan 2005, logic board replaced

Posted on Jan 24, 2010 8:53 PM

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Answer 1

Jan 24, 2010 10:57 PM in response to markabajian

According to

http://www.everymac.com/systems/apple/imac/stats/imacg5_1.820.html

which I believe is the profile for your iMac G5, the SATA interface is "1.5Gb/s." So if the drive has a jumper specifically for this setting, it should probably be set. But that does not necessary mean it will not work if you don't set it. Most SATA drives do not have this setting at all.

If you want to know if one way is better than the other, this may be a case where you need to try it both ways (unless someone here replies with an answer). If it does not even work with it OFF, then it probably needs to be ON. If it seems to work both ways, do things like time large data transfers to an external drive and startup time, to see if there is any difference in performance. If there seems to be no difference, then I would use it ON.

FYI, in case you have not seen them, here are the DIY instructions from Apple for the non-iSight iMac G5 models.

http://support.apple.com/kb/HT2278

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Answer 2

Jan 26, 2010 2:17 AM in response to markabajian

You will need to jumper the drive.

One of the best places to check on the experience of other users and also see hints about things like jumpers is here: xlr8yourmac drive database

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Answer 3

markabajian Author

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Feb 13, 2010 6:55 PM in response to Kenichi Watanabe

Kenichi,

Thank you for your prompt reply.

The Barracuda drive works without the jumper.

Please note that the DIY instructions you provided apply to Apple-supplied replacement drives. They do not explain how to disassemble the rails and re-assemble them for bare drives.

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Answer 4

markabajian Author

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Feb 13, 2010 6:57 PM in response to DaddyPaycheck

DaddyPaycheck,

I had checked the xlr8 pages already, before calling the Apple tech. Those pages were not clear on what specifically is required in my situation.

Thank you anyway.

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Answer 5

markabajian Author

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Feb 13, 2010 7:02 PM in response to markabajian

Thank you to those following this post.

I installed the new SATA II drive without the speed-limiting jumper. My iMac G5 recognized it. I installed Leopard on this drive, and it boots without a problem.

I have reached speeds of up to 15 MB/sec in transferring data to this drive. I believe that's about what I was getting on the previous SATA drive.

I have not attempted to connect this drive with the jumper in place. I don't see the utility at this time.

Thanks again.

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