Hi, I just registered to this wonderful community and I seek for some help. I was googling for a last few days how to add SSD "drive" to my iMac 27" (mid 2011) and I came across tutorial by ChargedPC.com http://blog.chargedpc.com/2011/05/2011-imac-ssd-install-guide.html as so many did. So I wanted to buy OWC Mercury Extreme Pro 6G 240 GB SSD which has no issues with speeding fans. But then I wondered, why wouldn't I add two OWC Mercury Extreme Pro 6G 120 GB SSD's and have twice the writing and reading speed. Of course I will have to throw out Optical drive but who cares. I never use it and with recovery partition from Lion I never will. I would just attach both of the SSD's with some quality Velcro tape and I think they will hold. I also know that 2011 iMac 27" has three SATA ports. Two SATA III and one SATA II. My plan is to plug in the SSD's in SATA III and HDD in SATA II. Problem is that I don't know which one is SATA III and which one is SATA II. Could some one clarify this for me? I also don't know which cables I need for the SSD that'll be instead of Optical drive. Are the cables from optical drive enough for SSD or do I have to buy new one? Which one? Thanks for your help and thoughts P. S. If you want I can keep you posted with pictures of installation and succession or failure of this adventure.