A) Redundant Array of Independent Disks, with a laptop, and external harddrive, is possible now with using a RAID 0 configuration, and USB 3.0 technology,http://news.techworld.com/storage/3200396/usb-30-will-enable-raid-performance/
HOWEVER, not with a laptop that has two harddrives already, and they are in a RAID 0 configuration.
(And they are in a RAID 0 configuration)
When setting up a RAID 0 configuration you are using TWO harddrives.
Data (Information) is split between the two drives. Turns two smaller drives into one large harddrive.
Means lose one harddrive, and you have lost all data.
Something to bear in mind.
1) You have two harddrives right now, and in a RAID 0 configuration.http://www.msi.com/product/nb/GT780DX-GT780DXR-.html#?div=Awards
"Dual SATA hard drives with RAID0 to double the transmission speed"
2) You won't be adding an external harddrive, and using it in a RAID configuration along with the two internal harddrives.
Not RAID 0, not RAID 0+1, not RAID 5,...Nada.
No RAID configuration.
-> USB 3.0 only supports RAID 0.
-> RAID 0 is TWO harddrives.
-> Using the external harddrive, you would have THREE harddrives in the equation.
3) You can only use the extra harddrive as an external harddrive, and only for storage.http://en.wikipedia.org/wiki/RAIDhttp://en.wikipedia.org/wiki/RAID_5#RAID_5
B) Your SSD harddrive is 95 percent full?
You know a computer slows down when the harddrive reaches 50 percent full, right? Not really noticed until it hits 70 percent, though. 95 percent full? Your laptop must be crawling at a snail's speed.
Suggest start deleting saved games, programs and applications you do not use. (No Windows programs, though)
Copy off photos, videos, music, and personal documents, then delete them from your laptop.
Supposed to perform a backup regularly, anyway.
Yes, I know it may be the Primary(?) harddrive, and the Secondary harddrive may not be recognized right now. Still need to keep the volume down for good performance.
Would do the same for the Secondary harddrive.
C) Yeah, I know. Main topic is laptop is overheating.
Get to the good stuff.
I realize you disassembled with no Service Manual, or guide; pictorial, or text.
You are to be commended. Really!
IMHO however, you have omitted some basic techniques when disassembling, and assembling a laptop, and a basic computer.
1) Did you makes sure the cables, (Wires), are going back through the same Channels, and Latches, as they did originally?
If not things do not go back together as they should. Cables can become pinched, therefore damaged.
Laptop and basic computer:
2) The Thermal Module used for cooling, consists of two copper Cooling Tubes, a rectangular finned Heatsink, and a Fan Assembly.
The copper Cooling Tube are connected to a small copper metal plate, and it is connected to a larger aluminum metal plate.
If a Thermal Pad is used, it should be carefully peeled off, and flown at the cat. It CANNOT be reused.
Once an imprint is made on a Thermal Pad, it won't contact the surfaces again the same way it did originally, if reused.
Also a Thermal Pad is a substance that is impregnated with Thermal Paste, and Thermal Paste dries up over time. Looses it's thermal conductivity properties.
Both the surface of the Processor, and graphics chipset, should be carefully scrapped clean with a plastic scraping device, (Old credit card?), and then followed with MANY Q-tips dipped in Isopropyl Alcohol.
93 percent is best, but 70 percent will do.
(50 percent is 50 percent Alcohol, and 50 percent WATER.
IMHO this = NO)
Isopropy Alcohol is EXTREMELY FLAMMABLE!
Use in a WELL ventilated area with NO sparks or flames present!
Then good Thermal Paste should be used.
Thermal Pad was also a spacer? Removing it leaves a gap?
Then you need to cut a new small piece of Thermal Pad, and also use Thermal Paste.
[Just in case, Primer;
The top of a Processor, and graphics chipset, are not perfectly smooth. A magnified view would detail, 'Hills, Valleys, and Pitholes'.
Neither is the surfaces of the metal plate/s of the Cooling Tube.
When the two surfaces are brought together, these imperfections create an air pocket.
Air is an Insulator. Not a Conductor.
Thermal Paste fills these voids, or imperfections, and is an excellent conductor of heat.
NO Thermal Paste being used; Or reusing a Thermal Pad, will cause overheating. Using old Thermal Paste can also lead to overheating.
Paste has lost it's thermal conductivity, or a large portion of it ]
MSI giving out a Service Manual to the consumer?
Fish will fall out of the sky first.
My MSI laptop 'stash',http://repair4laptop.org/disassembly_microstar.html
It's just basics, Tj Hafner.
Use basic guidance that you would use with all laptops,http://www.insidemylaptop.com/
For additional questions please post in a Comment.