Hey. Well, to make it easy, considering IDE/SATA hard drives:
1- Does RAID worth being used on a personal computer?
2- Does RAID slow down boot? If yes, does it change depending on whether the controller is on-board or connected on some "PCI" slot?
3- Is the difference, about performance, that significant, for example with "RAID 0", and does having more hard drives increases performance (more drives reading/writing... might help)?
4- Again, about performance, is there something better between having a "RAID" controller on-board or connected to a "PCI" slot?

Thanks in advance.

1. Raids are nice, even on a personal computer. It depends on exactly what you're doing with your computer. If its just basic usage, like web browsing and email then a raid probably wouldn't make any difference. They are faster, but you'll only see the extra speed if you're using the drives to their capabilities.

2. As far as I've noticed, my raid hasn't slowed down the boot process. It shouldn't matter if it's on a pci raid adapter or an on-board one, since its really only modules that have to be loaded.

3. I'm not sure about performance increases in raid 0 with the more drives being used. Maybe someone else can give some insight into this.

4. I think this last one depends on the hardware. Typically pci raid cards are better if you want to run a serious hardware raid, since many on-board controllers are only capable of running software ones, at least in linux. My Asus a7n8x deluxe is an example of this. If I had some extra cash I would probably buy a dedicated raid card for a pci slot and run a hardware raid.