I have a 15" mid 2010 mbp, 2.4GHZ i5, 8GB RAM. I have been thinking about speeding it up by installing a 128gb SSD on it to run my OS and my apps off and having a normal hard drive. Questions: 1. Should I keep my existing hard drive as my secondary disk or buy another one? I'm worried in case anything with having that disk in use means everything will still be slow. 2. I looked at the datadoubler but it doesn't say it is suitable for 2010 mbp. So what can I get to install 2 disks? 3. Finally, I know the samsung evo 840 seems to get the thumbs up. However, from what I've been reading certain SSDs have extra capability that's not usable on certain machines, SATA II maybe...(?) So would this samsung model be ok? Finally, I did search the forum, but I was unable to made head nor tail of all the info. I tried reading the sticky, but the wording just didn't make sense to me. EDIT: just seen there is a pro version of the samsung 840 series. Whats the difference with this?