What is the difference between the WinTV-PVR-250 and 350 models?
Both models will have the same capture and TV functionality. The PVR 350 adds FM radio, as well as a video output(S-video/Composite video), so you can output captured MPEG videos to an external monitor of VCR.
Video out is only S-Video or Composite, there is no RF output.
When Video Out is enabled, turning off the local playback will lower CPU usage considerably. To access that option, click and hold right mouse button then go down to video out and uncheck Local Playback. You can also turn off Video Out in the same menu selection.