Dual SSD's: How can I tell which one is in which slot? Does it matter?

lip5016

macrumors regular
Original poster
Jul 11, 2014
174
26
Hey guys.. so I just installed 2x SSD's on my MacBook Pro (one in main drive, one in optibay)..

When I first booted up OSX, I selected the drive which was at the "top" of the menu-list in every option.. I assume that this is the "main" drive-bay disk? Both of these drives passed hardware tests and seem to be working fine, I'm just not sure of whether or not I may have accidentally installed OSX/Macintosh HD onto the drive in the optibay vs. the main drive-bay.. I wasn't sure if maybe you're supposed to have OSX on the one in the main drive or not.. and where in "About This Mac" can I determine which volume is in which bay on my computer (without having to go thru the trouble of opening the MacBook Pro, disconnecting a drive, etc, etc)?

I just want to make sure that my configuration is all proper and if I accidentally installed OSX/Macintosh HD on the a less-efficient connection (if that is such a thing)! I already checked and spoke to Apple and have confirmed that my model has both 6G/SATA-III in the main drive, as well as the SuperDrive/Optical Drive.. Please let me know what you guys think! Thank you!
 

hallux

macrumors 68030
Apr 25, 2012
2,942
592
Most likely, the drive that's 'disk0' is the one in the HDD location while 'disk1' will be the drive in the Superdrive location.
 

lip5016

macrumors regular
Original poster
Jul 11, 2014
174
26
Most likely, the drive that's 'disk0' is the one in the HDD location while 'disk1' will be the drive in the Superdrive location.
****.. I've definitely got them switched then.. Does it make a difference in performance if they're both the exact same Samsung 850 Pro model (512gb), and they're both connected w/SATA-III (6G)?

Do you think that means I should re-install on the disk0 drive instead? Or does it matter since they're both connected SATA-III? Please let me know! Thank you!
 

Los Angeles

macrumors member
Sep 25, 2012
71
20
Wait What

You guys will have to excuse my ignorance... I am not very good at understanding hardware... I currently have a Retina Mid 2012 MBP. I have the 750GB SSD.. but I would like more storage... Am I understanding this thread that its possible to put in a 2nd Drive? Would it be another 750SSD?

J
 

simonsi

macrumors 601
Jan 3, 2014
4,850
734
Auckland
****.. I've definitely got them switched then.. Does it make a difference in performance if they're both the exact same Samsung 850 Pro model (512gb), and they're both connected w/SATA-III (6G)?

Do you think that means I should re-install on the disk0 drive instead? Or does it matter since they're both connected SATA-III? Please let me know! Thank you!
If they are both connected at 6G then no, it will make no difference. My SSD is in the optical bay, is my boot drive and connected at 6G, runs fine.

Just seen your other thread, if one drive is connected at a negotiated speed of 3G (probably the optical bay), and the other is connected (negotiated) at 6G (probably the main HDD bay one), then you should clone your boot drive to the 6G drive and swap the boot drive selector to that drive.
 
Last edited:

MarvinHC

macrumors 6502a
Jan 9, 2014
762
222
Belgium
You guys will have to excuse my ignorance... I am not very good at understanding hardware... I currently have a Retina Mid 2012 MBP. I have the 750GB SSD.. but I would like more storage... Am I understanding this thread that its possible to put in a 2nd Drive? Would it be another 750SSD?

J
That is only possible in the 'classic' MBP that has a superdrive (CD/DVD) - you use the space for that drive to put a second SSD in. No such possibility for the retina I'm afraid.
 

Los Angeles

macrumors member
Sep 25, 2012
71
20
That is only possible in the 'classic' MBP that has a superdrive (CD/DVD) - you use the space for that drive to put a second SSD in. No such possibility for the retina I'm afraid.

Thank YOU for the explanation. I guess Ill have to wait for a new model to come out with a bigger hard drive
 

MarvinHC

macrumors 6502a
Jan 9, 2014
762
222
Belgium
Thank YOU for the explanation. I guess Ill have to wait for a new model to come out with a bigger hard drive
Yes, the biggest you can configure these days is 1TB and the price tag is BIG.
If I were you I'd look into an external harddrive for additional storage. If speed is very very important to you, use an SSD as external drive, one of these for example via the USB 3 port:
http://www.amazon.com/Samsung-Elect...e=UTF8&qid=1411617373&sr=8-1&keywords=ssd+1tb

with a cable like this:
http://www.amazon.com/StarTech-com-...TF8&qid=1411617485&sr=8-14&keywords=sata+usb3

or in a HDD enclosure like this:
http://www.amazon.com/Optimized-Ina...UTF8&qid=1411617411&sr=8-1&keywords=ssd+usb+3

If speed is not so crucial just get a small 'classic' external HDD like this one:
http://www.amazon.com/Seagate-Backu...F8&qid=1411617557&sr=8-4&keywords=seagate+1tb

(just examples, plenty of options out there)
 

Los Angeles

macrumors member
Sep 25, 2012
71
20
Thanks again for the info. I really don't want to have an external hard drive. But thanks again for the info.

J
 
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