Heres a page from X1 Manual
Causes and cures
The exact cause of your audio problem will vary depending on the configuration of your computer
and/or the content of the project file you're working with. The majority of audio problems are caused
by one of the factors listed below. Read each of the topics below, in the order shown, and follow the
recommendations provided:
“The CPU is being interrupted by "background" activities having nothing to do with audio” on page
1124
“Cakewalk doesn't properly “recognize” your sound card” on page 1125
“The "I/O Buffer Size" may not be well matched to your hard disk” on page 1125
“Mixing latency may be set too low” on page 1126
“Your hard disk may be excessively fragmented” on page 1126
“Your project file may be excessively fragmented” on page 1126
“Your sound card's driver may be obsolete” on page 1127
“There may be a conflict with your video card or other multimedia streaming card” on page 1127
“Your sound card may have a conflict with another device in your computer” on page 1129
“Your project may simply be too "complex" for your computer” on page 1130
“Upgrade your computer hardware: more RAM, a faster CPU, and a faster disk drive” on page 1130