so why are you saying raid? if its all set to ata it wont be on a raid channel?
If that is the case then all is fine now you say c: lags so is this c: on main os or c: on hold os? as you said both drives are c: dependant on which os your on
You could run a scan disk on boot using the chkdsk /r command in console on the os drive thats lagging of course also enure its defragged? use something like diskeeper so you can resize the MFT if needed
