Depends on what kind of performance you're talking about. The Black drives will probably give faster transfer rates, but the Raptors will definitely have better access times.
Note, however, that RAID 0 doesn't really improve access times - all the drives will have access times just about as fast even if you keep them as separate, single drives.
Usually when people are trying to speed up their system to make it boot and start programs faster it's access times that are most important. Transfer rates are only important for copying or processing large files.
It depends on which generation of drives he's talking about. The 1st-generation Raptors had less dense platters and so their transfer rates weren't as fast as the higher-density 1TB drives, even though they spun faster. That's because they were updating the 7200RPM drives with higher density platters more often than they were updating the Raptors.
I just checked the spec sheets for the current-generation drives:
It's not that I need the speed really. It is more that i have them laying around collecting dust. So I was going to use them in a computer for my wifes family. It was cheaper going to one of those solutions then buying a ssd. So the raptors would be faster then correct in terms of access times and and a dead heat between transfer rates?
Putting drives in RAID 0, especially older drives, and especially for someones else's computer, and especially for a family PC, and especially if it is for someone in your family is not a very good idea, and entering into a discussion about the speed of such setup for the intended use of this system is pretty irrelevant.
Put the Raptor in they system as the OS drive, put a Caviar Black in as a storage drive, and leave RAID out of it.
Just some friendly advice, whether you decide to take it or not is entirely up to you.
I definitly see your point. I do however test all drives as if they are going into a mission critical enviroment. These drives are less then a year old and I make frequent images of them in that case would you still consider it more risk then it's worth?
Yes i make frequent images of the machine or atleast plan to after this change over. Do you think have the 4 raptors involves to much unneeded risk as compared to the 2 blacks? Even though say the 2 blacks have a potential for more data to be stored.
You'll get the same capacity whether you connect them as a single large RAID 0 set or individual drives. If you're just looking to make use of them the simplest and safest thing to do is to just hook them up individually.