I'm having an issue with FCP 7 -- periodic beach-balling (every five minutes or so). It's running on a nearly new Mac Pro with a 512GB SSD and 24GB RAM, and FCP is often the only open application.
I have found from two different sources (correspondence) that this can be due to the Mac Pro's older processor, which only supports 3G SATA transfer times for SSDs. I've heard that the iMac's i5 or i7 can support 6G SATA.
Long story short, are there FCP users out there who experience similar issues? What are people's thoughts on editing a big project (feature-length documentary) on a beefed up iMac versus the Mac Pro?
I can only share my experiences with the MacBook Pro (2009 Core2 Duo) and an SSD (OWC 3G) as the boot / applications volume.
I have never had the issue that you describe. My typical set up is to use my traditional hard drive for media storage (such as imported media and other assets) while setting my SSD as a scratch disk for quick renders and also faster exporting of files.
I highly doubt that 3G SSD speeds would cause a beachball problem, when even the slower SSDs are much faster than a typical internal drive.
Have you tried the Blackmagic diskspeed utility? I believe it is free on the Mac App Store. You should be able to confirm your read and write speeds are more than sufficient.
The intermittent nature of the problem (every 5 minutes), suggests to me that it is not an overall performance issue with the drive, but perhaps a configuration issue somewhere. I am perplexed though. It is fully possible that your SSD has a hardware issue as well, but I don't know how to test that other than swapping it.