Need Help: 4TB internal HDD not working inside iMac 24

[HardBoiled92]

Hi. Anybody have experience with using a 4TB internal HDD in the iMac 24? If so, what brand and model drive did you use? I need help with a puzzling 4TB HDD issue in my early-2009 iMac 24 (iMac9,1; OS X 10.6.8 Snow Leopard; 8GB RAM).

I'm trying to replace the original 1TB internal HDD with a Western Digital Black 4TB 3.5" HDD: model WD4004FZWX, SATA III, 7200 rpm, 128MB cache. I formatted the drive in an external USB enclosure, used SuperDuper! to clone the data from the original drive, and verified that the new 4TB drive can externally boot my iMac.

However, when I swapped the drives and tried to boot from the new 4TB drive internally, I got the flashing "?" folder symbol. I put the original 1TB drive in the external enclosure and booted externally from that, and the iMac does not even see the new 4TB drive. It's missing from the Desktop and Finder, and it's not listed in Disk Utility or System Profiler's Hardware Serial-ATA tree. I swapped the drives back, booted from the 1TB drive internally, and the Finder and Disk Utility see the 4TB drive externally, but as an unformatted disk ("The disk you inserted was not readable by this computer.")!

I thought the 4TB drive might be defective, so I exchanged it for a new one, but I got the same results with that one as well. Also, I tried resetting the PRAM and the SMC in the course of troubleshooting, but that didn't help.

At this point, I think the issue is with the iMac 24's NVidia MCP79 SATA controller not being compatible with the WD4004FZWX's disk controller, since the NVidia MCP79 is not fully compatible with a number of SSD controllers. So the NVidia MCP79 is finicky. I found instructions on the Western Digital website on using a jumper to restrict a SATA III drive to SATA II speeds, but the WD4004FZWX doesn't have a full set of 8 jumper pins (the drive has pins 3 & 5 only, but pins 5 & 6 need to be jumped):

https://support.wdc.com/knowledgebase/answer.aspx?ID=981

I'm planning to return the WD4004FZWX and try a different 4TB drive. Please let me know your experience or advice with using a 4TB HDD in the iMac 24. Thanks.

 

[nambuccaheadsau]

If you check out out the ifixit site for the 2006 iMacs, you will see a contributor named Dan has advised to get a 1.5Gb/ps Many of the 6Gb/ps SATA III have trouble communicating with the original 1.,5Gb/ps drives. His post begins 'Nope, Machead......". Towards the bottom of the poage.


https://www.ifixit.com/Answers/View/196585/Max+hard+drive+limit+on+an+Early+2006+iMac

 

[DeltaMac]

You also might try contacting Western Digital support directly, and find out if they have any help for you.
But, it really sounds like the W-D black and your iMac just don't talk to each other nicely. The curious part, to me, is that you were able to format, and get all your drive onto that 4TB drive, and you said you successfully booted to that drive while it was in the external USB enclosure. Did I get that part correct?
And then, the drive then went brain-dead, and wasn't in the same condition, even after you put that 4TB drive in the external case again. Just very strange. I was suspecting that the format was simply wrong (a block size that the drive controller doesn't accept), but that doesn't explain why the drive appeared to work at first.

nambuccaheadsau may have a valid point, too.
However, the 2009 iMac9,1 has support for 3Gbps SATA, so would that iFixit discussion apply here?

 

[RyanXM]

I have used the Toshiba MD04 series with success in the older iMacs. The Toshiba MG03 and MG04 has also worked without the need for jumpers. These are typically OEM drives.

 

[HardBoiled92]

Thank you for the replies, everyone.

@nambuccaheadsau: Thanks for the link. Both the NVidia MCP79 and original 1TB HDD are SATA II (I forgot to mention that in the original post), so it looks like a conflict between the controllers for the MCP79 and 4TB WD HDD.

@DeltaMac: I'll try calling WD support this morning. And you are correct with your summary. In the external USB enclosure, the 4TB drive was formatted, cloned, and successfully booted my iMac. Internally, the 4TB drive wouldn't mount or be detected. And when the drive was put back into the external enclosure, it came up as an unformatted disk! So the conflict somehow wiped the drive!

@RyanXM: Thanks for the recommendation! If WD support can't help with this issue, I'll try a Toshiba drive. Glad to hear they work. Were these also 4TB drives? And which iMac models used them successfully?

 

[HardBoiled92]

Update: I tried Western Digital support 2 weeks ago, but they weren't able to assist with the incompatibility between the WD4004FZWX HDD and my iMac or explain what the 2 jumper pins did. Eventually, the WD support tech recommended that I return the drive, which I did. Based on RyanXM's recommendation, I got the Toshiba 4TB MG03ACA400 HDD, and it's been working without issue. No problems with booting from the drive or with SATA II/III compatibility. According to Blackmagic Design's Disk Speed Test, the new drive has faster read/write speeds:

• Original WD 1TB Caviar Black HDD: 89.6 MB/s write, 89.9 MB/s read
• New Toshiba 4TB MG03ACA400 HDD: 155.0 MB/s write, 157.7 MB/s read

My thanks to RyanXM for the HDD recommendation!

I hope this information helps anyone else with an early-2009 iMac 24 (iMac9,1) that's looking to upgrade to a 4TB HDD.

 

[RyanXM]

Glad I could be of help! And glad you got it upgraded and working!