Multicam seriously is the way to go. I think you should be asking "How to make Multicam work on my hardware?" There is probably a way to get it working. If you're getting the dropped frames "warning", go into preferences and turn it off, ignore those warnings. If you're having serious playback issues, so bad you can't edit, then we can troubleshoot that.
What are the specs for your Mac and storage?
What cameras were these clips shot on?
You could just stack them on top of each other, mute and un-mute as needed (v), blade cut things as needed (b), but that's really the long way around.
Hi Letsshoot, Welcome to the forums
Ben beat me to it, think you have other issues. Having better info on computer, ram, type of storage and how it connects, (not USB2 I hope) and how full it is , need 15-25% free space on drive, would help trouble shoot. Also need to know what codec the clips are in.
Make sure you do a full shut down of computer before next attempt to edit. You might want to consider deleting preferences. (Hold down Command + Option keys while launching)
You can also use Activity Monitor to see if you are having RAM issues, under Memory Tab see how much RAM is wired, and how big the Swap Used is. If all RAM is used and large swap amounts, then you need more RAM. Make sure to shut down any other apps running that you don't need.
In general you should be able to create a 3 angle multi-cam with no issues on modern computers capable of running FCPX 10.3.4. I would say unless you are editing 4K or greater clips, you should be able to even create MC with native format, but certainly with Proxy.
Hope this helps, Greg
My biggest tip for performance is to open up the "Background Tasks" window. When you first bring in a bunch of clips into an underpowered computer, it's going to have a background task doing transcoding. Just go away and do something else away from your computer until that's done.
I learned that the hard way, trying to do 1080p/60fps video using 3 cameras with 2+ hours of content on a 2012 MacBook Pro.
Letsshoot wrote: ...Im new to fcpx. I want to edit three music clips. Multicam is not suitable as it keeps dropping frames even though I am using proxy and optimised media...
You don't necessarily need optimized media; to some degree that and proxy are redundant. However to use proxy after generating the files you must engage proxy mode in the viewer. Then after editing you must change that back to optimized/original, otherwise the export will be at proxy resolution.
It is uncommon on a contemporary machine for three camera material to be sluggish when using proxy. Is like that immediately or only after you added certain effects?
It is possible you built both proxy and optimized media, did not engage proxy mode so it's using optimized, which is about 8x the size of camera-native H264. This in turn places great stress on the I/O system which if marginal can cause dropped frames or sluggish behavior. Three-camera multicam multiplies that by three, so the I/O burden vs single camera native H264 would be 8 * 3 or 24 times the I/O rate.
To give a specific example, a 1080p H264 codec from a Canon DSLR produces about 30 megabit/sec or 3.75 megabytes/sec. However using three-camera optimized media this becomes 90 megabytes/sec, which is close to the performance limit of a 5400 rpm bus-powered USB 3 portable drive. The same content from a 4k camera at 100 megabit/sec would require 300 megabytes/sec, which is above the I/O bandwidth of any single-platter drive.