Raid 0 Problem

[N-Gen]

Hey guys, I've been running 2 Western Digital Scorpio Black 320GB (2.5") drives in raid 0 for the last 2 months without a single hiccup. They have been in use longer as both were present in laptops I have and I figured I should use them for a better purpose. One shows it has been powered on for ~720 days, the other ~360 days. The older one is about roughly a year older than the other. However recently (about 3 - 4 days ago), one of them started constantly spinning down while under usage. I only use my raid setup for games and have been only been playing WoW lately.

I did notice load time increases...sometimes annoyingly long. HD Sentinel shows both my drives at 100% health, no bad or weak sectors. WD diagnostics tool fails mid test on the quick and fails as it starts on the extended test. While not running any game, even immediately after, the drives just spin down and idle perfectly, no random spin up attempts therefore no spin downs.

I know it's a raid drive spin down from the noise apart from the increased load times because the 2.5" drives have a distinct spin down noise to them. I haven't bench marked, which was probably a good idea, but I'm at school so I will have to try it later on.

Any help would be appreciated, thanks in advance.

[N-Gen]

Bench results seem pretty ok to me, I have no idea what's going on with them.

[BlackOmega]

I see you have a bunch of drives, how can you be sure its those drives that are actually spinning up or down as opposed to another drive?
Also, if those drives are failing a diagnostic test thats a pretty good indication that onr is going bad. Backup whatever you need off of those drives and test them individually.
An old Maxtor drive I have did the exact same things before it started getting lots of bad sectors and what have you.

[N-Gen]

I can tell it's one of them because their spin down noise has a distinct sound to it, unlike the other drives, been living with them for quite some time now so I'm able to tell, and the others only have data that is not being accessed at the time of the raid use, apart from the ssd. The problem only occurs during gaming...during benchmarking there was no spin downs. I think WD diagnostics can't cope well with raids, gonna try the controller stuff.