I have a mid 2010 iMac with a 1TB WD HD, I'm running out of room.. what are my options? 1. External hard drive for media files.. too slow? 2. Swap hard drive with 2TB 7200rpm drive.. i read the stock drives have special firmware that control the fan speed, etc.. so that you can't swap drives? 3. replace superdrive with 512GB SSD, boot off that, use original 1TB drive for media..? or does the mid 2010 imac have an unused 2nd sata port for SSD?