Hi qap, if the 2010 model as far as I have been able to determine - and don't quote me on this but do check out the many SSD drive threads here - the fan runs at a constant 1100rpm for the SSD if using an SSD in place of a hard drive; Apple make a jumper short (modders fitting an SSD in absence of a hard drive apparently use a staple and insulating tape) available from spares vendors for around $19, which causes said fan to run at a constant 1100rpm. As far as I know in situations where there is both a hard drive and SSD and the SSD is the boot/apps drive, fan speed is again around 1100rpm as per the temperature of an untaxed hard drive.