Any ideas on the best Config for RAID-0 on the Precision M6800 using SSD's (and the mSATA slot)

Question

Hi,  I have an M6800 on order that has a single 500GB 7200RPM hard drive.  I am going to upgrade the storage the day it arrives (removing the 500GB drive and not utilizing it at all).  I plan on setting up an SSD RAID-0 array and want to take advantage of the mSATA slot if possible. 
I thought of using the 2TB 2.5" Seagate/Samsung Momentus SpinPoint ST2000LM003 hard drive for storing unused vhd\vhdx files as well as video and photos,  then using an SSD RAID array for the OS, Applications, Data and any active vhd's. 
Is it possible to set up RAID-0 using the mSATA SSD slot and the primary internal hard drive slot?  I want to use those 2 drive connectors so I can still use the 2TB 2.4" regular notebook hard drive without removing the Blu-Ray Writer?  I plan to write video to Blu-Ray discs that will be stored on the internal 2TB drive, so removing the optical drive is something I want to avoid.
As a general question, Is there any advantage to using RAID with SSD's, or would a single 1TB mSATA SSD in the mSATA slot be nearly as fast in real world use as a 2 disk SSD RAID?  Would I have a noticibly quicker boot time and application load time if using SSD RAID?  I know the speed test specs show large increase in performance, but will the computer really run a lot faster with 2 x 500GB SSD in RAID-0 as opposed to getting a single 1TB SSD card for the mSATA slot?
I was planning on getting the Samsung Evo 840 SSD 2.5" drive and the matching Evo 840 mSATA card.  There is a Samsung 850 series drive, but it is only available in 2.5" (mSATA is not available in the 850 as far as I can  tell).
Please suggest the best solution that is compatible with the M6800 or provide any information that might help.
Thanks

Answer 1

Hi Ential, 
Thanks for the info, I thought my question would go unanswered forever.  I posted the question in January, and I have since set up the computer.  Below I will detail my research and the configurations of drives that I have used on my M6800 since the time I posted the question you answered.  Perhaps the results of my research and testing might help you. 
I originally I bought the same exact model SSD's that Dell sells with the computer thru their website;    the LiteOn 512GB drives (mSata & SATA),  I configured them in RAID-0.  The LiteOn drives are sold under the brand name Plextor,  I found the proper model numbers by looking at the SSD drive firmware upgrade file from the Dell support website.
From what I understood,  my RAID-0 drive consisting of the 2 LiteOn drives had impressive performance using the AS SSD benchmark program,  I was getting performance scores over 1600 back in February.
I have since changed to the Samsung EVO 850 1TB drives and again created a RAID-0 drive,  one SATA drive and one mSata drive totaling 2TB.  This drive array is getting AS SSD performance scores over 1900.  I contacted Samsung to get some advice on the configuration of the drives and I got some interesting advice that seemed to help a lot:
Samsung told me to leave 200GB of the drives (100GB each) unallocated when I partitioned the drives,  this is generally referred to as "overprovisioning" (which you probably knew already).  I initially thought that overprovisioning could only be configured by the Samsung Magician software and a special process needed to take place to tell the firmware to utilize a specific amount of drive space for overprovisioninng.  The Samsung support agent told me that the Samsung SSD firmware (on both mSata and SSD) automatically uses any unallocated space as overprovisioned space (they are basically the same thing to the drive firmware) and it increases performance in a very  noticible way when you have sustained use of the drive and/or durinng the time in between the TRIM process (garbage collection).  The unallocated space is used by  the firmware to write data to while blocks of data are awaiting internal wiping initiated by the TRIM process.
Since I have 200GB of unallocated space,  I am able to have more sustained deletion and writing of data between TRIM/Garbage Collection runnninng than I would ever utilize without affecting the performance of the drive.  Basically most SSD drives have performance decrease throughout  the day until the TRIM process is completed by the drives firmware,  so Samsung instructed me to leave at least 10% of the drive space unallocated to limit that problem.  Smaller drives likely need a higher percentage of space unallocated as compared to larger drives since the daily amount of read/write operations is typically the same regardless of drive size.   The amount  of space left unallocated/overprovisioned is based upon the amount of read/write operations done on any given drive,  not based on the size of the drive itself.  If you run drive intensive applications, you would then want to overprovision more GB of drive space,  if you have light use of the drive then you can overprovision/unallocate less GB of drive space (all of the configuration info regarding overprovisioning and TRIM was given to me by a Samsung specialist over the telephone - I called their tech support phone number and got a storage specialist to talk to me). 
I will look into the SATA version on the optical bay,  I never thought about that with this computer.  My prior computer was a Dell XPS 17 3D (L702X) notebook which had 2 internal 2.5" SATA,  in which I installed an optical bay drive.  On that specific computer the optical bay was technically an SATA 3,  but due to design constraints it couldnt run at that speed since there was voltage leakage across some pathways in the chipset when the optical bay has read-write throughput that is typical of a hard drive (as opposed to much less data transfer typically seen on an optical drive).  The M6800 can be factory configured with an optical bay hard drive, so I suspect it can support one properly.  The XPS 17 was not available with an optical bay drive as an OEM configuration from Dell,  so it couldnt be expected to properly support one.  The design issue with the voltage leak across the chipset pathways on the XPS 17 was known by Dell,  but due to the low bandwidth of an optical drive, the problem never occured with any of the factory OEM configurations.
It is possible that the optical bay  hard drive offered by Dell (the exact OEM Drive installed by Dell) could have an internal limitation to SATA 2 due to a similar design limitation.  It would not be surprising if an SATA channel designed for optical drives had SATA 2 speed since I suspect there is no SATA Optical drives that could use more than 3GB/s of data anyway. 
I purchased 2 of the 2TB 2.5" hard drives that Dell uses for OEM configurations for this computer,  they are Samsung 5400 RPM drives.  I have one in a 2.5" internal bay and the other in the optical bay - I converted my Blu Ray Recorder/Writer drive to an external drive.  I will do some extended time speed tests on the optical bay drive to see if its performance matches the internal drive (which  is the same exact model drive - I have 2 of the same Seagate 2TB drives installed with the same firmware).
I use the pair of 2TB drives to store .vhd and .vhdx drives for test platforms for Hyper-V machines.  The virtualized servers with high hard drive utilization get moved to the SSD RAID-0 array,  the rest are stored on the 4TB rotational drives. 
If you have any questions or comments for me,  please let me know.  I will see what info I can find on the optical bay SATA revision for this notebook,  I am very curious to find out if it is in fact SATA 2.  I will let you know what my test results are,  I will try to use the AS SSD benchmark program,  I believe it will work with rotational drives,  otherwise I will find another benchmark utility - do you have a recommendation on which to use?
Thanks again for your info and for pointing out the possible limitation of the optical bay..