I have couple of questions regarding RAID 0.. please bear with me..
1. Does the hard drives you put in RAID 0 have to be the same capacity?
2. Reading online, I found that you get almost %100 read and write improvement with 2 drives in RAID 0.. what about loading, booting improvement (again I'm talking about only 2 drives in RAID 0, compared to a single drive setup)?
3. this question may seem stupid, but please pardon my, I'd say, innocence.. Can you only RAID0 operating system to improve only boot and load?
1. They don't absolutely have to be, but if they aren't the same size/speed you will only get to use the size of the smaller drive x2, and drives of different speed is just a bad idea.
2. 100% improvement is greatly misleading imo. It likely would be faster then a single drive, but in select cases only. You would probably see a bit quicker boot time, and load improvements.
3. You can place whatever you would like on a raid set. Running a pair for WD raptors in raid 0 for OS used to be a pretty common setup, but today the majority of people who would want performance like that go with an SSD.
I wouldn't bother messing with a raid set, and would save to buy an ssd which would be way faster then any raid 0 set with mechanical drives and be a simpler configuration to work with. You also double the risk of data lose when running a raid 0 set.