... I very much convinced that Apple should never have released iMovie Version 10.
The given functional scope is very, very, very poor and it is impossible to work with larger libraries. i.e. my library covers 5 years of video material split into 300 events nicely sorted by date in Version 9, whereas Version 10 offers my only an alphabetic list without any indication of date/time stamp!!!!
All the shame goes to the apple release manager, who seem *NEVER* to have really worked with more than 10 events! It was also no-where mentioned, that "sorting by date" was rereleased!
Since I couldn't find any workaround in Version 10, I've back-migrated to Version 9 (... and deleted the newly created Version 10 video library by hand to prevent from doubling all video material!!!!

)
I hope that many more people complain about Version 10, so that Apple will start fixing the Version 10 and to bring it function wise to at least par with Version 9!
Therefore "OpenCL-capable graphics card support" is really not priority number 1!