Onboard raid or to buy raid card? O.o

Okay so I heard if you use onboard raid it will affect your cpu usage? Is that true? I seen raid-cards on newegg and they are pretty expensive....Is it really worth it getting two identical hard drives and putting them in raid 0...? Will I see uber low loading times and such? xD

so when im planning on buying Asus P5Q (http://www.newegg.com/Product.aspx?Item=N82E16813131297) Could some one tell me if this mobo has "fake" or "real" raid controller on it?

Hardware raid normally is available on expensive server/workstation motherboards only. The P5Q has software raid (Intel Matrix Raid), but it doesn't require much CPU power - some raid cards are worse. Google "ich10r benchmarks" for interesting reviews.

RAID 0 is arguably not 'worth it' for most people but gamers who want the fastest level load/data read times possible it is not only worth it, but required.

RAID 1 is arguably not 'worth it' for most people but users who demand data reliability and for another layer of backup, it is required.

RAID 1+0 is arguably not 'worth it' for most RAID users but if you have the room for the right drives and want the best of speed, hot-fix reliability and efficient storage it is the right choice.

RAID 5 is arguably not 'worth it'. No really.

Don't worry about the difference between software or hardware raid unless you are doing constant sustained I/O operations, your CPU utilization for RAID is in the low single digits for modern CPUs and transparent in almost all circumstances.

mobo's cheap software raid can sometimes go nuts and lose the array. The disc themselves are just fine but the system wont recognize the raid array no matter what you do and then you're screwed...

or so I'm told

If you are just striping for better disk mix performance, then you will not experience a lot of CPU usage from a software RAID. If you are mirroring for better reliability, then you will see a little CPU activity, but if you are running multiple cores, you won't notice anything.

If you need to run RAID 5, you will find that your CPU will have a lot more activity as the software RAID has to do all the XOR calculations on the CPU. If you find you need this level of data reliability, then spending the money on a hardware RAID is probably not beyond your reach.

As far as whether or not you will have a hard time recovering a software RAID, you will have just as hard a time recovering should your hardware RAID fail. But I can't even begin to tell you how much more flexible a software RAID is over a hardware RAID. Not being tied to a particular piece of hardware makes recovery that much easier, and on most servers, I have found that the CPU drag of a software RAID isn't even noticeable.

To be honest, I have had better luck recovering Linux MDDM RAID arrays than I have had with any other, software or hardware. With today's CPUs, you will actually find that for a lot of the tests, software RAIDS are competitive with hardware RAIDS, and well-written software (and frequent patches) will save you from data corruption. I have installed several hardware RAIDs from reputable companies where I actually had to go through at least four or five ROM flashes before I was able to overcome data corruption. I can't emphasize it enough...BACKUP, BACKUP, BACKUP. If it's important enough to require a RAID array that has parity or mirrors the data, back it up.

For what Kari is describing, this behavior happens usually when a RAID member loses either power or connectivity, and you will experience this discombobulation whether you are running a hardware or software RAID. If you back up religiously (like you should) it shouldn't take too long to recover the volumes. Again, not all RAID systems are alike, and you will experience different levels of recovery depending on how well the hardware or software was designed. I will reiterate, I have had the best experience recovering Linux MDDM RAIDs, even when this has happened. As far as the Nvidia RAID software is concerned, it all depends on how well it was coded. Bad code == bad recovery methods. Choose your solution wisely.

For the record, I have seen some very expensive hardware RAID arrays do this too. The difference is that a hardware array will usually recover with a reboot, even if the parity information gets whacked (as long as you haven't lost more than one member for RAID 5). Well written software RAIDs will recover in much the same way. And you aren't stuck without a means of recovery should your hardware fail. Just reinstall the array software on a new box, connect the drives, and away you go.