OK, so some more info...

I thought I would install OSX via the eSATA AHCI JMicron controller instead.

Therefore eliminating the onboard ICH9R AHCI.

I could not get the thing to install... the installer saw the disk - and would let me partition it etc... but the install process was just taking forever.. every now and again a small blip of data would be written to the hdd.

Booting in to OSX with the ICH9R set to IDE (boot disk) and the JMicron eSATA set to AHCI (spare disk) I can confirm that this is definately hdd related and not a system hang.

i.e. Copying to the IDE is fine, copying to the AHCI stalls.

However, because the AHCI is not my system disk, I can continue to use the operating system - in this instance only the copy process hangs.

So so so odd...

I'm gonna partition one of my other drives now...

Also, maxmem=2048 made no difference.

Cheers,

Jon.