Insanely Slow RAID-0, Brand New Samsung 850 Pro's (Pics)

I'm just curious if you resolved this issue or not? I'm planning the same setup for my 2011 17" MBP with the same drives. I think its a sweet setup and would love to see it work! But I don't have the time to tinker in case it doesn't. Thanks in advance!

Sorry to hear that. I did some more research on this and it seems to be a specific problem to the 2011 15 and 17 MBP's. Here is some more info that I found about it:

http://eshop.macsales.com/item/OWC/DDAMBS0GB/#comp_notes

http://blog.macsales.com/11895-2011-macbook-pro-sata-problems-resolved

http://forum.crucial.com/t5/Crucial-SSDs/2011-MacBook-Pro-SSD-in-optical-bay-REA D-BEFORE-ATTEMPTING/td-p/102620

Bottom line is that the 850's are Sata III 6GB/s drives and therefore are not stable or reliable in the optical bay. I actually had this problem on my existing setup and didn't put 2 together that it is also why the RAID setup may not be working for you. I believe there is a way to change the negotiated link speed of the opti drive so it runs at 3GB/s which is proven to be stable but you probably can't do a RAID setup that way.

It's a shame Apple can't invest a little bit in bringing back a beefed up 17 MBP. I'm strongly considering a Lenovo W540 as my next machine.

I just wanted to follow up on this thread because I went ahead and gave an attempt at getting this to work on my 2011 MBP 17" and so far so good. I've been running for about 1 week now and am consistently getting 900+MB/s R/W.

I am using dual Samsung 850 Pro (256GB) and I purchased this expensive Optibay from MCE which is what I think is making the difference: http://store.mcetech.com/Merchant2/merchant.mvc?Screen=PROD&Product_Code=OBSXGB- XTRM

I also did not do a clean install but I did a clone using Carbon Copy Clone of my existing OS onto the RAID array.

It's a nice setup and hopefully if it remains stable, I won't need to upgrade for another couple of years.

I have two samsungs 256gb pros, 840 & 850 in a raid 0 config and I have run into so much problems getting it to work. I couldn't get the yosemite boot disk to work so I finally used the internet recovery and installed lion and it worked great. I was getting almost a 1g w/r, I upgraded to mavericks... fine there as well but after yosemite I have been having issues with my computer. Im not sure if I need a new power supply because it says I have full charge but lately it will shut off and I think because it has done this so much it corrupted my system files. Do you think its power related or is it because of the raid setup in yosemite? btw how did you do a clone of your os. Maybe I should do that instead. Really disappointed with this new OS! If you shoot any help my way I'd appreciate it

BTW i also purchased the MCE Optibay Extreme.

Hello,

This has NOTHING to do with your MAC, it is a Samsung drive problem with the 3d NAND chips in the newer drives.

I too have the same problem, where my Samsung drives will get 500MB/s reads and write when attached to a single SATA port, but if I put 2 drives in RAID0, the speeds drop to less than 200MB/s for reads and writes.

While I own several MAC's, the info I talk about came from a PC I have that had 4 x Crucial SSD's from 2012 (the M4 series SSDs). They would get around 800MB/s reads and write on a LSI 9260-8i controller on a MSI-7522 motherboard with a Xeon X5670 2.93 CPU (clocked to 4GHz). Ironically the CPU came out of a Mac Pro that died, but the CPU's were still good so I used them in 2 PC's I built. So, this is not a slow machine, and I thought I would upgrade the SSD's in RAID0 to get faster speeds. Well, I have read on other sites of people having the same problem with Samsung drives. I used 2 x 500GB EVO drives, and they do better as single drives in JBOD that is any type of array.

The answer I keep finding is the 3d NAND chips have issues when being placed under another controller, and they don;t handle it well so the speeds are drastically slowed. Funny that a MAC user is seeing the same problem that PC folks are having, which rules out the OS or configuration or the SATA controller, as all those are different and the only common factor is the Samsung EVO drives.

Good luck, but you are in the same boat and until someone makes a controller or drive fix to enable these new EVO drives to run at full speed when in an array you will have to use them as JBOD, sorry to bring the bad news. I used one to upgrade my 2008 MBP laptop, it gave it a nice boost over the spinner that was in there before.

Dave