I've run into a slight problem but thankfully it appears that my Mac Mini isn't as bad at it first seemed to be in FCPX. I had been playing back video and it was choppy, so I transcoded it to Proxy, which seemed to playback okay when playing the clips outside of FCPX and just using Quicktime. However, inside the program, even with Proxy media, it was still very choppy.
However - when I got this Mac Mini from an online sale, the only downside was the onboard audio didn't work, so a cheap USB adapter was included, which I thought was fine. I tried unplugging the adapter and playback in FCPX was much improved without any stuttering. This is a great find - except for the part where I really need audio to get my editing done.
It looks like the adapter is a USB 1.0 part, and was limited to 12 Mb in speed, and may have been holding up the video playback. It works fine for everyday tasks, but when it comes to FCPX work, it is a major bottleneck. Can anyone recommend a different USB 2.0 adapter that they may have already used in FCPX without issues? I tried to plug in my DV camera in case it would let me output audio to there, but that seems to be a no-go. I'm almost ready to just run to the local Best Buy and try the Sound Blaster X-Fi Go! Pro they have for $40. I was looking at some Firewire options, but they get expensive quickly, and I just need an audio output, not a whole interface with multiple ins and outs.