When you can you should use sub-busses to run FX on your audio. Also, might be sound card but here is a workaround. Make sure you have downloaded and installed all of the latest drivers. Also, make sure you defrag your drive to less than 3 or 4% fragmentation as this will always cause a problem. That can be a great source of sporadic processing. If you are in final production then incease the buffer size to handle the load. If you are still recording then keep the buffer size small. Make sure you save all of the original tracks and try to implement below for added recording capacity. It is all about buffers and latency.
In the old days I had a 4 track tape mixer. This method is know as ping-ponging tracks. I used to mix down three tracks to one track. Then you have three tracks open. A little extra planning track by track wil allow you to mixdown the audio tracks into logical groups, export those mixdowns as wavs, and then bring the mixdown in as a single track. This will reduce the workload on your processor and sound card. You should then be able to continue recording while listening to the mixdown without sputters and dropouts. Don't worry, the next step will make you able to mix down everything from scratch as long as you save all of the original individual tracks for later use.
Now when you go to final production you can increase the buffer size to handle the load of all the wavs and bring them all back in as single tracks for the final mixdown. ASIO requires you to play with the settings quite a bit to avoid droputs. Again, being smart and using busses with common FX's is the key. Even when rendering you can experience a dropout if you overwhelm your processor with too many effects on individual tracks. There will never be enough hard drive, or CPU, or buffering in this world. If you are cranking that many vocals then you are pushing the edge of the envelope. Try to always clip out the dead spots in an audio track using the clipping tools. That way you are only processing the real audio and not a lot of "silence". The CPU looks at a clip. Same processor is running dead silence so get rid of that if you can.
Learning these techniques well will guarantee that you never find yourself in the middle of a major production unable to move forward or backward. There is always a work around. Good luck!