FCP X 10.0.7 slows down to crawl

After not working with FCP X for about 6 weeks (lots of aother distractions) I started again 1 week ago. However, by that time I had installed the latest update (10.0.7). Now FCP X came down to a crawl every time after a little while of running. I becomes even unresponsive for excruciatingly long times.

Meanwhile I have traced down a few problems on my computer:

- Interfering Startup items (with apple Care)

- Hard disk space getting eaten up and repeated problems on the hard disk that needed repair (with Disk Utility): Here, I ultimately found that Diskdrill, which I had installed, but rarely used, wrote a whole bunch of invisible files to the point that programs were affected. I uninstalled the program and made sure that the invisible folders and files weren't there anymore.

Now FCP X is still slowing down. The symptoms:

- after a while I can't interact with the program anymore. Each click produces response times that go into the seconds, sometimes minutes. (spinning beach ball)

- background rendering becomes very slow and seems to interfere with real time inputs, which it never did before

- System Memory is used up except for a symbolic 12-20 MB (I have 8 GB installed) according to Activity Monitor. Plenty of free space after quitting FCP X, of course

- Hard disk space is still eaten up over time when running FCP X (starting with 200 GB free space, then running down to ≈130 GB). At this point, the system complained twice the no more Application Memory is available on the Startup Disk and asks me to force quit programs. Even the steps until FCP X is forced to quit take me many minutes to complete. Once FCP X has quit, the OSX System and other programs run fine again, and the free hard disk space is slowly coming back over several minutes.

By the way, I have recently restricted the number of applications running even more than before (I didn't see problems in the past) to just Activity Monitor (to see what's going on) and Console (to take a peak at errors and warnings.

I had a session with a FCP X specialist transferred from System support yesterday. We went over several items. Upon suggestion, I experimented with turning off automatic rendering. However, even that didn't work much better. I moved all but the one Project that I was working on into another folder to temporarily hide it. I get reasonable performance for a few minutes, but then I am back to square 1.

Any similar experience with FCP X 10.0.7? Does this update need significantly more RAM so that I have to upgrade to, say, 16 GB?

Comments and thoughts appreciated

Eberhard