The following is from the Hints and tips thread in the Technical Support forum, under "SCREEN STUTTERS/PAUSES", and I have added the bold emphasis...
left out the Processes part of this reply hmmm yes sounds could cause this with "on-board" sound as you have in bold
but a dirty over processed pc and messy hard drive will cause more stutter
My system
System Model Dimension XPSGEN5
System Type X86-based Pc
Processor x86 Family 15 Model 4 Stepping 4 GenuineIntel ~2999 Mhz
Processor x86 Family 15 Model 4 Stepping 4 GenuineIntel ~2999 Mhz
Adapter Description NVIDIA GeForce 9800 GT
Adapter RAM 1.00 GB (1,073,741,824 bytes)
Resolution 1280 x 1024 x 75 hertz
Name Creative Audigy Audio Processor (WDM) ZS2
3.00 gb Ram
about 8yrs old I run 75fps