I wish i could say i was specific to an interface, so here goes.
Samson CO3U USB mic direct to USB port(s) tried both ports same results
M Audio Mobile Pre with a different mic
Macbook Pro built in mic.
All resulted in large latency. In Garageband i had the following tracks
TR1 Drum pack
TR2 Bass pack
TR3 Acoustic guitar (M Audio Mobile Pre)
TR4 Mandolin (M Audio Mobile Pre)
TR5 backing vocal (Samson CO3U/USB)
TR6 was to be a lead vocal track experiened too much latency.
I even locked all the tracks except TR6 no difference.
The machine is a Macbook Pro running Yosemite 10.10.3
2.9Ghz Intel Core i7
8GB 1600 Mhz DDR3
Intel HD graphics 4000 1024MB
800GB storage/748GB available storage
I also run Adobe Audition for Voice Over work utilizing the same microphone with minimal to zero latency.
NO OTHER PROGRAMS WERE OPEN DURING GARAGBAND
I did not have these issues with the previous version of Garageband 😕
Any help would be appreciated.