I have two 150Gb Raptor hard disks on my new setup.

I intend to put Vista on one 150GB Hard disk and XP MCE 2005 on the other.

If I was to combine these two hard disks into a single RAID 0 array, despite the fact that I will be splitting the array in half again for the two OS installs would I gain any performance boost?

Also, what pitfalls will I need to watch out for when building/using this RAID array?

Yup, Just create the array and make it 2 partitions when you go to install the OS. You will still see a performance gain.

Only real pitfall with RAID 0 is the increased risk of complete data loss in a drive failure. If I remember the numbers correct, your chances of complete drive failure and or data loss on a bad drive in a single drive setup is less than 1% but in a RAID 0 setup the risk is ~9%. So, back up your data!

IMO, RAID 0 is an easy way to speed up load times and increased overall 'snappyness' of the OS.
Do some searches and you can find some pretty good benchmarks.

The raptors overall dont need the boost in performance but ive been doing it for a while and have had no problems with mine so knock on wood.

I don't understand those numbers. Data backup is obviously important, but you still have a chance to lose data no matter what lol. Raptors have a 5-year warranty so that's a start =D

My two pence.....
If you are asking the question then my answer is do not do it.
ST is correct, a RAID 0 will speed up load times of your os and some applications. It is great when you need to access very large uncompressed data files. Working with NLE video editing and animation for instance (what I use it for), it can add quite a bit of performance.
The down sides I have personally experienced:
You break the stripe, you lose the data.
Running 2 os's off the same hard drives can cause problems for back up programs.
Over clocking can cause the stripe to fail.
A power outage during a read/write operation can cause the stripe to fail.
A software bug can cause the stripe to fail.
A buggy BIOS can cause the stripe to fail.
My observations of the various reviews of RAIDS... They are significantly faster at benchmarks but not for many applications. Those that take a long time to load, such as large games, are usually slow due to the need to uncompress the files. A few due benefit though.
I am constantly looking to squeeze that last bit of performance out of my system, but I balance that with the risk of having a failure. After several years of trial and error, my main system is 4 os', XP Pro, XP 64, Vista Ultimate 32 and 64. The XP's are on their own partitions on their own 300 gig WD SATAII, same as Vista. I have 2 WD 500's in a RAID 0 for data only. 1 WD 300 for swap files/cache files. I do daily backups of the RAID to a external 1394 drive.
Those drives you have are fast and will perform real well. The first time your RAID fails, the time you spend reloading and rebuilding will more then offset any savings you gain.

mobo57 your downsides seem to be putting me off making a RAID array for the two drives. The facility and circumstances warrant it so it is tempting but by the sounds of your personal experiences it sounds like RAID 0 is rather fragile. So much as resetting or turning off the machine while it is say loading a game or stuck in a heavy task will kill the whole array.

Are you really saying that RAID 0 is really that delicate??? :-O

Yes

i have had a raid0 array for 3 years with the same two drives and have had no problems (even with many random BSODs when Vista first came out). But if you are going to use it I would recommend a third drive as a backup for important irreplaceable files.

I have been using RAID for about 9 months now and I LOVE IT!!! I am only using 2 WD 160GB hard drives at 7200 RPM but the difference is very noticable. From the time I push the power button, log on, and double click the icon to start my game is 1min. That is awesome. I hate waiting and being able to start loading a game in only one minute from power on is great.

As for how fragile it is? I don't really know if I can confirm mobo57's statements. I have never had any problems with it, and it has randomly restarted on me a few times. I have never had a power loss as I have a battery backup on my system but I have never had an array break down.

Also, I consider myself a fairly heavy user and because of that, I make sure and reformat my drives at once every 6-9 months. Because of this, I always have my important files saved on another drive. That way, in a worst case scenario, I will only loose my most recent data. Just back up your data and you won't have to worry. It is a good idea even if you don't use raid.

Well, as has already been stated, and as my real world experience proves, RAID will let you load the OS faster. It will let you access large files faster. It will evey start games faster.

It will not help you play games better. It will not make your FPS higher. It will not make hardly anything faster/better after that program is already open.

Add to that, it is much more prone to problems, so it requires more diligence in backing up your data. Finally it makes basic maintenance/troubleshooting a bit harder since not all diagnostic programs work as seemlessly with RAID.

So, make your choice based on those pro's -vs- con's.

I ran a RAID 0 array for about a year. I'll never do it again. For me the benefit was not worth the extra pain. You may have a very different experience than I did.

As far as the numbers go...

In a single drive you have a less then 1% chance of drive failure (as in physical drive failure)

With a RAID 0 you have at least 2 drives required to create the Logical Dive. But, with RAID 0 even if one drive fails you lose everything. There is some logarithmic function that defines the fact that if any single drive has a ~1% chance of failure that x amount of drives in a given array will increase the risk factor of data loss if catastrophic drive failure occurs in any of the drives in the array by amount n

Get it

Have used raid 0 for 4 to 5 years. My 2 B/U computer (An old p4 prescott is about 4 years old) Only on problem, shortly after loading OS I bumbed the HDD dring a write - Dumb.

My current system (Built Jan 07) has 2 pair of Raid 0 drives, One pair has XP Pro and the Other pair Has Vista 32. Use Bios to select which drive to boot from.

Performance gain depends on usage and file size. I notice very little difference in performance only daily task (Don't game)

If it was me I probably would not raid 0 the two Raptor. One for OS and programs, One for Data.

Go for it, you get the same space in the end and a performance gain.

Found it

http://techreport.com/articles.x/2525/2