Help with choosing a HHD for optical bay in early 2011 13" MBP

[dapperdee]

I just purchased this HDD for my optical bay in my 13" early 2011 MBP.

WD 750GB Black SATA III 7200 RPM 16 MB Cache WD7500BPKX for $67.24

After reading that the optical bay uses SATA II connections which will downgrade the hard drive's SATA 6 Gb/s speeds to SATA 3 Gb/s. For what I spent could I have purchased a slower 1Tb HDD and still get similar results from having in the SATA II optical bay?


FYI I have this in the main bay: Samsung 840 EVO 120gb

 

[simonsi]

After reading that the optical bay uses SATA II connections which will downgrade the hard drive's SATA 6 Gb/s speeds to SATA 3 Gb/s.

That isn't guaranteed, my early-2011 runs the SSD (Crucial 120GB M500), in the optical bay at 6G, as well as the 1TB HDD in the drive bay at 6G. Not sure what the dependencies are but it isn't 100% SATA2 in the optical bay...

 

[Mike Boreham]

SATA 3 = 6G in the optical bay is very variable. I had two 2011 MBPs, one didn't even see a 6G device in the optical, and the other appeared to be working fine, but SMART data showed there were a lot of UDMA CRC errors. This is where the data has to be requested to be resent, and is typically due to cabling errors which is the root of the 6G in optical bay problem on the 2011 MBPs (inadequate shielding).

It is much better to put a SATA 2/3G device in the optical bay. The options are

1. Find a SSD which is SATA 2...rare nowadays.

2. Put an older SATA 2 HDD in the bay. HDDs used to always be SATA 2 but new ones are mostly SATA 3 now, even though HDDs cannot make use of the extra speed of SATA 3.

3. Buy one of the recent HGST 1Tb 7200 or 1.5Tb 5400 HDDs which are SATA 3, and use the downloadable program "HGST Tools" to reset it to SATA 2. As noted an HDD will not operate any slower for being SATA 2 which provides more than enough connection speed for any HDD.

HGST Tools has to be burnt to a CD and booted from the CD to do this. No other manufacturer offers this capability.

has a lot more about this topic including in post #30 on page 2, a downloadable copy of HGST Tools.

EDIT It is not correct that the Optical bay of 2011 MBPs use SATA 2, it would be better if it did. It is SATA 3 (as you will see from System Report) but it is SATA 3 which doesn't work with SATA 3 devices. Apple only intended it to be used with the SATA 1.5 superdrive. If it was genuinely SATA 2 there would be no problem because a SATA 3 device would cheerfully work at SATA 2 speed, as was the case in my 2010 MBP.

Be aware that you may need to remove the HDD in the optical bay to refit the superdrive when you want to update the firmware of the SSD in the main bay, or if you need to install windows for Bootcamp. External optical devices won't do these jobs (at least without a lot of hassle and risk for the layman).

 

[dapperdee]

thank u for the info