Large capacity HDD issues

iMac A1225 EMC2134

High capacity HD issue(s?).

I am in the process of upgrading the HD in my iMac (C2E 2.8GHz powerplant, model number A1225; EMC2134; Model Identifier iMac7.1, Order number MA878LL). Original HD: a Seagate 500GB SATA. The plan: exchange for an as silent and cool as possible running 3TB one.

Had already done some recon on my iMac: lifted the glass panel and undone the bezel, discovered lots of dust in the innards, closed the iMac. Posted a question about that a few days ago. Got usefull answers on the dust removal.

However, it looks as if I am embarking on a somewhat trouble-laden voyage.

The initial idea: put the new high capacity HD in a present MacPower external FW800 cabinet and have the system softwareDVD in tandem with the migration assistent clone or copy the internal HD to the new high capacity HD. Test and if neccessary, adapt, untill it all works flawlessly, only then exchange or swap the HD units.

In concert with a quite large and well reputated computer -not Apple only- dealer, I decided for a WD 3TB RED-series HD: WD30EFRX. A so called WD RED, the label sports the text-string: NAS Hard Drive. According to the salesperson, it could also operate in any 'normal' personal desktop. The inverse -a 'normal' HD into a NAS- however, according to the salesperson, is in general not a good idea.

Installed it into a MacPower cabinet, connected via FW 800 to my iMac and….. it did not recognise it. Got the message: disk improperly removed, disk is unreadble, would you like to reformat it? Options: 'Yes' or 'No'

Selecting 'No' leads to the same message again, i.e. nowhere.

Select 'Yes' and one can reformat. Choose a name and select Mac OS extended journaled, just one partition.

The next thing was a great and unleasant surprise: I ended with a single partition volume not larger then 840GB instead of the expected 3TB.

The 'Get Info' revealed an exact identical number.

Swapped the WD 3TB for a still in foil, unopened, unused 1TB Hitachi/Deskstar HDS721010KLA330 I had still laying around. With that one everything went flawlessly, after formatting it showed up as 999GB.

Opened up the MacPower cabinet, took out the HD and the printed circuit board.

Found out the main chip is an Oxford OXUF934DSB-LQAG, the bridge between FW800, FW400, USB2.0 and eSATA on the one end and SATA on the other end.

That one seems to be the suspect, as far as I managed to find out, it is unable to handle large capacity (over 2TB) HDs.

Can anyone in these conference(s) confirm this or shine some light into this?

From here on, I see two options:

- put the 1TB HDS721010KLA330 into my iMac, or,

- put the WD RED WD30EFRX straight into my iMac, install OSX and let the migration assistant do its job.

The 1TB HDS solution is easy, I can play this by the earleir mentioned scenario, but, it only doubles the present storage.

To go the WD trail, to me it looks wise to try to find out whether the controller (SouthBridge?) in my iMac can handle a 3TB HD, and if not, what is the maximum it can. Does anyone here know?

About the WD RED NAS Hard Drive. Some but not all of the so called experts like system operators and IT-guys state: A NAS type HD can and should only be used in a NAS and although they look and feel identical, are identical in size and show the same looking connections as 'ordinary' HDs, they cannot and should not be used in an ordinary desktop. It simply will not work.

So there could be something of an issue here, but what? Anyone here?

Final question: As I have been told, next to the signal-receptacle on the HD, I should place some jumper since my iMac cannot deliver nor receive the GB/s recent HDs can accept or produce. Correct or could be or …?

Thanks for reading.

Greetings from Continental Europe,

Feike Hoogenbos